\NUFACT1 
 
 ANDARD SPECIFICATION 
 
 STRENGTHENING AND WATERTIGHTZNINCi 
 
 CEMENT MORTARS AND CONCRETE 
 
 PRACTICAL APPLICATION 
 
 USE IN MORTARS 
 
 BYE.W.LAZELL, PH.D. 
 
.Engineering 
 
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UNIVERSITY OF 
 DEPARTMENT OF CIVIL ENGINEERING 
 BERKELEY, CALIFORNIA 
 
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 Hydrated Lime I 
 
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 .11 
 
 History, Manufacture and Uses in 
 
 Plaster - Mortar - Concrete 
 
 1915 
 
 A Manual For 
 The Architect, Engineer, 
 Contractor and Builder. 
 
 By E. W. LAZELL, Ph. D. 
 
 Member American Institute of Chemical Engineers. 
 Member American Society Mechanical Engineers. 
 Member American Society for Testing Materials. 
 
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 Engineering 
 Library 
 
 Copyright 1915 
 
 by 
 E. W. LAZELL, Ph. D. 
 
 PUBLISHED BY 
 
 JACKSON-REMLINGER PTG. CO. 
 PITTSBURGH, PA. 
 
CHAPTERS 
 
 Chapters Page 
 
 Introduction 7 
 
 I Historical 9 
 
 II Chemistry of Lime 11 
 
 III Classification of Lime 21 
 
 IV Manufacture of Lime 24 
 
 V Slaking Lime 34 
 
 VI Manufacture of Hydrated Lime 41 
 
 VII Properties of Hydrated Lime 46 
 
 VIII Use of Hydrated Lime in Sand Mortars 49 
 
 IX Use of Hydrated Lime in Concrete 63 
 
 X Advantages of Hydrated Lime over other forms of Lime .... 79 
 
 Appendix I Useful Data 81 
 
 Appendix II Standard Specifications for Hydrated Lime. . . 84 
 Appendix III Quantities of Materials for One Cubic Yard 
 
 of Plastic Mortar . 87 
 
 LIST OF ILLUSTRATIONS 
 
 Page 
 
 Pyramid of Cheops Frontispiece 
 
 Lime Cycle 17 
 
 Pot Kiln 25 
 
 Field Kiln 26 
 
 Draw Kiln 27 
 
 Vertical Steel Kiln 28 
 
 Vertical Steel Kiln, With Stack 29 
 
 Vertical Producer Gas Kiln 32 
 
 Modern Installation of Lime Kilns Equipped to Use Producer Gas 33 
 
 Clyde Hydrator 43 
 
 Kritzer Hydrator 44 
 
 Second National Bank Building, Toledo, Ohio 51 
 
 Equitable Building, New York City 61 
 
 Leader-News Building, Cleveland, Ohio 64 
 
 Dam, White Salmon River, State of Washington (Under Construc- 
 tion) 65 
 
 Dam, White Salmon River, State of Washington (Completed) .... 67 
 
 Concrete Road, Garret Co., Maryland 68 
 
 Armory, York, Pa 69 
 
 Reservoir, Waltham, Mass 72 
 
 Ambursen Hollow Dam, Portland, Ore 76 
 
 Hotel Oregon, Portland, Ore 78 
 
 821018 
 
INTRODUCTION 
 
 IN presenting this book to the public, the purpose has 
 been to direct the attention especially of architects and 
 
 builders to the comparatively new form of lime "Hydrated 
 Lime," which possesses many advantages over the older 
 Lump Lime. 
 
 The art of using lime is one of the very oldest connected 
 with the building trade and was probably brought to its 
 greatest perfection by the Greeks and Romans. Since these 
 ancient times until very recently little or no improvement has 
 been introduced in the preparation of plaster or stucco made 
 from lime. Probably the reason for this is the time and care 
 required to slake the lump lime used to prepare the mortar. 
 With the use of hydrated lime the time required to slake and 
 age the quick lime is done away with. 
 
 It has been my aim to collect together in convenient 
 form the available data on this subject. Use has been made 
 of previous publications and much information has been ob- 
 tained from the technical press. Especial mention must be 
 made of the works of Vitruvius, Vicat, Miller and Hodgson 
 and the various publications of the different Bureaus of the 
 United States Government. It is hoped that the book may 
 prove useful in calling attention to the characteristics of 
 hydrated lime and describing its various uses. 
 
 1915 E. W. LAZELL, Ph. D. 
 
HISTORICAL 
 
 CHAPTER I 
 
 r I "MIE use of lime as a binding material or mortar for holding together 
 stone and brick originated in the remote past. It is probable 
 some savages, having used stones composed of limerock to con- 
 fine their fire, noticed that the stones were changed by the action of 
 the heat. A passing shower slaked the lime to a paste, thus the dis- 
 covery was made that the paste was smooth working and furnished a 
 better material than clay to fill up the holes and crevices in their crude 
 dwellings. From the discovery of the fact that burned limerock gave 
 a material which slaked with water to a paste, it was but a step to the 
 addition of sand in order to produce a mortar. 
 
 The art of using mortar in some form or other is as old as the art 
 of building or as civilization itself. Evidences of the use of mortar are 
 found not only in the older countries of Europe, Asia and Africa, but 
 also in the ruins of Mexico and Peru. The remains of the work of these 
 ancient Artisans are evidence to us of the enduring qualities of lime 
 mortar as well as the skill and knowledge possessed by the user. Miller 
 in his work on mortar states "Plastering is one of the earliest instances 
 of man's power of inductive reasoning, for when men built they plastered; 
 at first, like the birds and beavers, with mud; but they soon found out 
 a more lasting and more comfortable method, and the earliest efforts of 
 civilization were directed to plastering. The inquiry into it takes us 
 back to the dawn of social life until its origin becomes mythic and pre- 
 historic. In that dim, obscure period we cannot penetrate far enough 
 to see clearly, but the most distant glimpses we can obtain into it shows 
 us that man had very early attained almost to perfection in compound- 
 ing material for plastering. In fact, so far as we yet know, some of the 
 earliest plastering which has remained to us excels, in its scientific com- 
 position, that which we use at the present day, telling of ages of experi- 
 mental attempts. The pyramids of Egypt contained plaster work 
 executed at least 4000 years ago, and this, where wilful violence has not 
 disturbed it, still exists in perfection, outvying in durability the very 
 rock it covers, where this is not protected by its shield of plaster." 
 
 The earliest known examples of the employment of mortar in 
 masonry are presented by the pyramids of Egypt. Vicat in his cele- 
 brated treatise on Mortars and Concrete, states: "The Egyptian 
 monuments present without doubt the most ancient and remarkable 
 
examples which we can quote of the use of lime in building. The mortar 
 which binds the blocks of the pyramids, and more particularly those of 
 Cheops, is exactly similar to our 'mortars in Europe. That which we 
 find between the joints of the decayed buildings at Ombos, at Edfou, 
 in the Island of Phila, and in other places, gives evidences by its color, 
 of a reddish very fine sand mixed with lime in the ordinary proportion. 
 The use of cements (limes) was therefore already known two thousand 
 years before our time; perhaps it would be easy to carry that epoch 
 still farther back, were we to consult the ancient monuments of India, 
 and the Sanscrit books, if they speak of the ancient relations of Egypt 
 with that country; but this would be to attach too much importance 
 to an inquiry, more curious than useful." 
 
 At a very early period the Greeks used plaster consisting of a true 
 lime stucco of most exquisite composition, thin, fine and white. The 
 houses of the simple citizen were ornamented with stucco which for 
 whiteness, hardness and polish compared well with the Parian marble. 
 Thus at the time of Pericles and Plato, the art of plastering had made 
 great progress. From the Greeks the Etruscans, of middle Italy, gained 
 their knowledge and the Romans in turn learned the art of plastering 
 from them. Greece became a Roman province in 145 B. C., and the 
 loot of it gave a great impetus to Roman art. Our knowledge of the 
 Roman methods of building and their use of material is largely derived 
 from the writings of Vitruvius. Vitruvius was a military engineer 
 under Julius Ceasar in his African campaign and was an architect under 
 Augustus. On all matters relative to Greek and Roman architecture, 
 Vitruvius should be consulted, since according to his own confession 
 his work contained all the knowledge that the Greeks possessed of 
 the art of building. Pliny the elder, in his natural history, and 
 Palladius, have added nothing to what Vitruvius had said before them. 
 The writings of Vitruvius will be referred to later in other chapters, 
 since his monumental work on architecture remained a standard refer- 
 ence book until well into the 18th Century. 
 
 The Arabians and Moors both became experts in plastering as is 
 evident by the splendid plaster work still to be seen on the Alhambra. 
 
 As early as the beginning of the 16th Century, the art of plastering 
 had made considerable progress in England and "The Plasterers Com- 
 pany*' was incorporated in 1501. 
 
 This brief review of the art of plastering as practiced by the Ancients, 
 will give an idea of the possibilities of the use of lime as well as proving 
 its enduring qualities. It is indeed sad to state that the present status 
 of the art does not nearly reach the perfection attained by the Greeks 
 and Romans, and it is with a wish to interest the public in the various 
 uses of lime mortar that this treatise was undertaken. 
 
 10 
 
CHEMISTRY OF LIME 
 
 CHAPTER II 
 
 ANY change which alters the composition and structure of matter 
 is a chemical change. A familiar illustration of this is the burning 
 of coal in which case both the composition and structure are 
 changed. It therefore follows since the structure and composition of 
 lime are changed by burning that a chemical reaction has taken place. 
 If the changes brought about by burning and slaking lime are to be 
 understood some knowledge of chemistry is necessary. 
 
 From a chemical standpoint, the changes which take place in the 
 manufacture of lime from limestone and the subsequent changes in 
 slaking and hardening are comparatively simple and do not involve 
 an extended knowledge of chemistry. In order to render the subject 
 clear, the various chemical terms involved will be explained and denned. 
 
 All matter is made up of one or more elementary substances, or 
 chemically speaking, all matter is made up of one or more elements. 
 An element is a primary form of matter which cannot be reduced to a simpler 
 form by any means known to science. There are some 80 of these elemen- 
 tary forms of matter known, and of these only about a dozen are involved 
 in the chemistry of lime. These elementary substances combine with 
 each other forming compounds in a certain known definite manner. Thus 
 a compound is the product resulting from the union of two or more dis- 
 similar elements. 
 
 Modern science recognizes three divisions of matter, Mass, Molecule 
 and Atom. Mass alone is appreciable to the senses. The other divisions 
 being far too minute to be reached by any power of observation. Mole- 
 cule is the term used to designate the smallest particle of matter that can 
 exist and still preserve the properties of the substance. It is formed by a 
 union of atoms which may be like or unlike, few or many ; it is constant 
 and regular in the disposition of its parts and bound together by strong 
 forces. The use of the term "atom" is from theoretical rather than 
 experimental considerations. Experiment has shown that a definite 
 quantity of each element always enters into combination, and theory 
 assumes that the smallest quantity entering into any combination is an 
 "atom." An atom can be defined as the smallest part of an element that 
 can enter into combination with another element. 
 
 11 
 
Although the atom in all cases is too small to be weighed individually, 
 the relative weight of each kind of atom has been carefully obtained as 
 the result of experiment. The weights of the various atoms have been 
 determined relatively by comparing them with hydrogen (the lightest 
 known element) which is taken as unity or one. These relative weights 
 arc called the "Atomic Weights." 
 
 TABLE No. 1 
 
 Atomic weights of the common elements 
 
 Name Chemical Symbol Atomic Weights 
 
 Hydrogen H 1 
 
 Oxygen O 16 
 
 Carbon C 12 
 
 Calcium Ca 40 
 
 Magnesium Mg 24 
 
 Aluminum Al 27 
 
 Iron (ferrum) Fe 56 
 
 Silicon Si 28 
 
 Sulphur S 32 
 
 NOTE The atomic weight is given to the nearest whole number as 
 this is sufficiently accurate. 
 
 The atomic weight of an element means that the weight of its atom 
 is so many times heavier than the weight of an atom of hydrogen. For 
 example, the weight of an atom of oxygen is 16 times greater than that 
 of an atom of hydrogen. 
 
 For convenience abbreviations are used for all elements. These 
 abbreviations are known as Chemical Symbols. Chemical Symbols serve 
 not only as an abbreviation for the name of the element, but the chemist 
 employs them to indicate the composition of the compound and the 
 number of atoms of the element in the compound. Thus the symbol 
 for calcium carbonate is written CaCO 3 . In which "Ca" stands for 
 calcium, "C" for carbon and "O" for oxygen. The symbol further 
 indicates that there is present in each molecule of calcium carbonate 
 one atom of "Ca," one atom of "C" and three atoms of "O." If the 
 atomic weight of the elements are inserted in the place of the symbol, 
 we have Ca = 40, C = 12, O = 16, O 3 = 48, total 40+12+48 = 100, the 
 molecular weight of calcium carbonate. The molecular weight of a com- 
 pound therefore is the sum of the weights of the atoms making up the com- 
 pound. 
 
 Knowing the molecular weights of a substance arid the elements 
 of which it is composed, it is possible to calculate its percentage 
 
 W 
 
composition. As an illustration, take calcium carbonate, the percentage 
 of each element present is: 
 
 Ca 40/100 = 40% 
 C 12/100 = 12% 
 O 48/100 = 48% 
 
 Calcium carbonate can also be considered as composed of calcium 
 oxide (CaO) and carbon dioxide (CO 2 ). 
 
 Calcium oxide (Ca+O) 40+16= 56 
 
 Carbon dioxide (carbonic acid gas) (C+O 2 ) 12+32= 44 
 
 100 
 
 Therefore, there is present in calcium carbonate: 
 56/100 = 56% CaO (lime) 
 44/100 = 44% CO 2 (carbon dioxide) 
 
 The compounds of the above elements most useful to the student 
 of lime are the oxides, hydroxides, hydrates and carbonates. These 
 various compounds of the elements given in Table No. 1 are illustrated 
 in Table No. 2. 
 
 TABLE No. 2 
 
 Elementary 
 Substance 
 
 Union of Two or More Elementary Substances 
 
 or 
 Element 
 
 or 
 Compounds 
 
 
 With Oxygen 
 Oxides 
 
 With Water 
 Hydroxides 
 Hydrates 
 
 With Carbon Dioxide 
 Carbonates 
 
 Name 
 
 c 
 
 1 
 
 i 
 
 Name 
 
 C/3 
 
 3 _b 
 
 1^ 
 
 Name 
 
 I 
 
 Molecular 
 Weight 
 
 Name 
 
 V) 
 
 Molecular 
 Weight 
 
 Hydrogen 
 
 TT 
 
 i 
 
 Water 
 
 H 2 O 
 
 18 
 
 
 
 
 
 
 
 Oxygen 
 
 O 
 
 16 
 
 
 
 
 
 
 
 
 
 
 Carbon 
 
 c 
 
 12 
 
 / Carbon 
 \ Dioxide 
 
 C0 2 
 
 44 
 
 
 
 
 
 
 
 Calcium 
 
 Ca 
 
 40 
 
 ( Calcium 
 | Oxide 
 ( Lime 
 
 CaO 
 
 56 
 
 Calcium 
 Hydroxide 
 
 Ca(OH) 2 
 
 74 
 
 Calcium 
 Carbonate 
 
 CaCO 3 
 
 100 
 
 Magnesium 
 
 M 
 
 24 
 
 C Magn'm 
 j Oxide 
 (. Magnesia 
 
 MgO 
 
 40 
 
 Magnesium 
 Hydroxide 
 
 Mg (OH) 2 
 
 58 
 
 Vlagnesium 
 Carbonate 
 
 M g C0 3 
 
 84 
 
 Aluminum 
 
 Al 
 
 27 
 
 ( Alumn'm 
 j Oxide 
 (. Alumina 
 
 A1 2 3 
 
 102 
 
 Aluminum 
 Hydroxide 
 
 A1 2 (OH) 6 
 
 156 
 
 
 
 
 Iron(Fermm) 
 
 Fe 
 
 56 
 
 f Ferric 
 I Oxide 
 
 Fe 2 3 
 
 160 
 
 Ferric 
 Hydroxide 
 
 Fe 2 (OH) 6 
 
 214 
 
 
 
 
 Iron 
 
 Fe 
 
 56 
 
 ( Ferrous 
 I Oxide 
 
 FeO 
 
 72 
 
 Ferrous 
 Hydroxide 
 
 Fe(OH) 2 
 
 90 
 
 
 
 
 
 
 
 ( Silicon 
 
 
 
 
 
 
 
 
 
 Silicon 
 
 Si 
 
 28 
 
 \ Oxide 
 
 SiO 2 
 
 60 
 
 
 
 
 
 
 
 
 
 
 1 Silica 
 
 
 
 
 
 
 
 
 
 Sulphur 
 
 s 
 
 32 
 
 f Sulphur 
 \ Dioxide 
 
 S0 2 
 
 64 
 
 
 
 
 
 
 
 13 
 
BURNING The chemical change which takes place in burning lime 
 consists in destroying the bond between the calcium oxide and carbon 
 dioxide. This change is illustrated by 'using the chemical symbols in 
 the form of an equation and for a perfectly pure calcium carbonate the 
 chemical change can be illustrated as follows: 
 
 Calcium carbonate + heat = calcium oxide + carbon dioxide 
 (limestone) (lime) (gas) 
 
 CaCO 3 +heat = CaO +CO 2 
 
 100 + heat = 56 +44 
 
 This equation shows that the calcium carbonate has been broken 
 up into two dissimilar substances by the action of heat, one of which is 
 a solid (lime) and the other a gas (carbon dioxide) . Further, it indicates 
 that 100 parts by weight of calcium carbonate yield 56 parts by weight 
 of lime, and that 44 parts by weight of carbon dioxide are driven off by 
 heat. 
 
 In the change produced by burning, the gas (carbon dioxide) is 
 carried out of the kiln together with the products of combustion of the 
 fuel. Nothing but the carbon dioxide is removed, except any moisture or 
 organic matter which may have been present in the stone. The solids, 
 lime, magnesia and all other substances, remain in the burned lime. 
 
 If the limestone contained 5% of impurities, such as silica or clay, 
 these would have remained in the burned product. In this case in 100 
 parts of the impure stone there would be 95 parts of calcium carbonate. 
 These 95 parts of calcium carbonate would yield 95/100X56 = 53.2 parts 
 of calcium oxide, the total matter remaining after burning would be 
 53.2+5 or 58.2 parts of impure lime, since the 5 parts of impurities can- 
 not be removed by burning. 
 
 The percentage composition of the burned lime would be: 
 
 53.2 
 
 = 91.4% calcium oxide 
 
 58.2 
 
 is 
 
 8.6% impurities 
 
 58.2 
 
 The presence therefore of 5% of silica or clay in the original limestone 
 has reduced the amount of lime (calcium oxide) in the burned product 
 from 100% to 91.4% or nearly 9%. 
 
 In a similar manner the burning of a dolomitic limestone may be 
 illustrated as follows: 
 
 14 
 
Dolomite -f- heat = Dolomitic lime 
 
 Calcium and magnesium carbonate +heat = calcium and magnesium oxide +carbon dioxide 
 
 CaCO 3 , MgCO 3 +heat = CaO, MgO + 2CO 2 
 
 100 84 (184) +heat= 56 40 (96) + 88 
 
 The percentage composition of the dolomitic lime would be as 
 follows : 
 
 56 
 - = 58.34% Calcium oxide (CaO) 
 
 i/O 
 
 40 
 
 = 41.66% Magnesium oxide (MgO) 
 
 yo 
 
 One hundred and eighty-four pounds (184 Ibs.) of dolomitic lime- 
 stone yield 96 Ibs. of dolomitic lime or 52.17% (96 -=-184 = 52.17%): 
 that is 100 Ibs. of dolomite yields only 52.17 Ibs. of dolomitic lime, con- 
 sisting of the oxides of calcium and magnesium. 
 
 From the preceding equations it will be seen that the amount of 
 impurities present in the stone increased the yield of the burned product, 
 although at the same time it decreased the amount of oxides of calcium 
 and magnesium present in the burned material (5 Ibs. of impurities 
 present in the stone decreases the amount of the oxides of calcium and 
 magnesium contained in the burned product to about 91%). Further 
 it will be noted that 100 Ibs. of dolomitic limestone gave only 52.17 
 Ibs. of burned material, while 100 Ibs. of high calcium limestone gave 
 56 Ibs. of burned material, thus the presence of magnesia decreases 
 the yield from 100 Ibs. of stone. 
 
 SLAKING OR HYDRATING LIME 
 
 As is well known, when quick-lime is treated with water, heat is 
 generated and a product is formed which has an entirely different char- 
 acter than the original quicklime. This indicates that a chemical reac- 
 tion has taken place which can be expressed for the two groups of limes 
 as given below: 
 
 High calcium quicklime + water = high calcium hydrate 
 CaO +H 2 =Ca(OH) 2 
 
 56 +18 =74 
 
 In this reaction 56 parts by weight of high calcium quicklime have 
 combined with 18 parts by weight of water producing 74 parts by weight 
 of dry hydrate. This dry hydrate contains the original amount (56 
 parts) of quicklime, but this material is not present as quicklime since 
 
 15 
 
it has chemically combined with the water. In case more than the 
 exact amount of water necessary to form the chemical hydrate is present, 
 this water is simply mechanically mixed with the hydrate forming a 
 lime paste. Calcium oxide is the only compound present in the lime 
 which actively combines with water, in the ordinary methods of slaking. 
 For dolomitic quicklime the reaction of slaking is expressed by 
 the following equation: 
 
 Dolomitic quicklime + water = Dolomitic hydrate 
 CaO MgO +H 2 =Ca(OH) 2 MgO 
 96 +18 = 114 
 
 By comparing this equation with the one for high calcium quick- 
 lime it will be noticed that less water has been combined in the slaking. 
 The reason for this is that the magnesium oxide contained in dolomite 
 is rendered inert at the temperature of burning and does not combine 
 chemically with the water, but remains present in the hydrate as mag- 
 nesium oxide. Thus dolomitic hydrate consists of a mixture of calcium 
 hydrate and magnesium oxide. It is for this reason that it requires a 
 greater weight of dolomitic quicklime to produce the same weight of 
 hydrate. The amount of caustic oxides present in the dolomitic hydrate 
 is greater than in the high calcium hydrate. The above equation was 
 calculated for a pure dolomite containing 58.5% lime and 41.5% 
 magnesia. 
 
 HARDENING The hardening of lime mortar is due to the lime and 
 magnesia present in the mortar combining with the carbon dioxide of 
 the atmosphere. The chemical change that takes place can be illustrated 
 by the following equation: 
 Calcium hydrate + Carbon dioxide = Calcium carbonate + water 
 
 Ca(OH) 2 + CO 2 =CaCO 3 +H 2 O 
 
 74 +44 =100 +18 
 
 Magnesium oxide + Carbon dioxide = Magnesium carbonate 
 
 MgO +C0 2 =Mg CO 3 
 
 40 +44 =84 
 
 From the foregoing explanation, it will be seen that lime passes 
 through three distinct chemical phases in its change from the stone to 
 the hardened mortar. These three phases form a cycle, and in the end 
 lime has returned to its original form. These three changes have been 
 illustrated and are given below: 
 
 1st Burning CaCO 3 +heat = CaO + CO 2 
 
 2nd Slaking CaO +H 2 O = Ca(OH) 2 
 
 3rd Recarbonating (hardening) Ca(OH) 2 +CO 2 =CaCO 3 +H 2 () 
 
 These changes have been graphically illustrated by the author as 
 the "Lime Cycle." Page No. 17. 
 
 16 
 
LIME|CTCLE 
 
 Showing the Sequence of the Changes Produced by Burning, Slaking and 
 
 Hardening, and that these Changes Form a Complete Cycle; the 
 
 Lime Returning to its Original Carbonate Form. 
 
 Copyrighted, E. W. Lazell, 1911 
 
 17 
 
A familiarity with the chemical terms and the changes which take 
 place in the manufacture and use of lime has a further advantage both 
 to the manufacturer and user in that it renders easy the interpretation 
 of the results of a chemical analysis of limestone and lime. This can best 
 be explained by starting with the analysis of a natural sample of lime- 
 stone and dolomite and following the two cycle change produced by 
 burning and slaking. 
 
 High Calcium Dolomitic 
 
 Chemical Terms Symbol Limestone Limestone 
 
 Per Cent. Per Cent. 
 
 Silica SiO 2 1.00 .93 
 
 Alumina A1 2 O 3 ) Qft o Q 
 Ferric oxide Fe 2 O 3 J 
 
 Lime CaO 54.24 32.73 
 
 Magnesia MgO .80 19.37 
 
 Carbon dioxide ) , T T ... v CO 2 ) ,,0 ft /t KQ 
 
 1 .r . > (Loss on Ignition) TT Q f 43 . Uo 4o . 58 
 
 All the above ingredients may be classed under three heads; im- 
 purities: silica, alumina and iron oxide; material removed by burning: 
 carbon dioxide and water; and the lime ingredient: lime and magnesia, 
 the only two materials which confer valuable properties on the burned 
 product. 
 
 It is possible from the above analysis to calculate the composition 
 of the lime which would be produced by burning either of the above 
 stones. The amount of material indicated by loss on ignition is that 
 portion which is driven off, all the other ingredients remaining in the 
 burned product. It follows therefore, that from 100 parts of the above 
 high calcium stone there would remain after burning only 56.94 parts 
 of high calcium lime (10043.06 [loss on ignition] =56.94). The quan- 
 tities of the various ingredients other than those included in loss on 
 ignition are present in the lime; therefore, the percentage composition 
 of the burned lime is calculated as follows: 
 
 10006 
 
 on 
 
 Al 2 3 +Fe 2 8 ^T94 = l ' 58% 
 
 CaO !t4/ = 9. 
 
 MgO ^ ~= 1.40% 
 
 18 
 
The composition of the lime produced from the dolomitic lime- 
 stone is derived in a similar manner: 
 
 AlA+FesO, = .73% 
 
 Ca " = 6 
 
 These illustrations show that in order to derive the composition of 
 any lime produced from a stone of known analysis it is only necessary 
 to divide the percentage amount of the ingredient by the difference 
 obtained by subtracting the percentage given for the loss on ignition 
 from 100. 
 
 The calculation of the composition of the hydrates derived from the 
 above limes by slaking is not quite so simple, still nothing is involved 
 more complicated than the rule of three. As has been stated before, 
 lime is the only compound present which combines with water, and this 
 combination takes place according to the equation 
 
 CaO+H 2 O = Ca (OH) 2 
 56 +18 = 74 
 
 or each 56 parts by weight of lime give 74 parts of hydrate; then the 
 95.26 parts of lime would give: 
 
 56:74 as 95.26:X X = 125.88 
 
 100 parts of the high calcium lime would yield on hydrating as follows: 
 SiO 2 No change 1 . 75 parts 
 
 Al 2 O 3 -hFe 2 O 3 No change 1 . 58 
 
 CaO Change to hydrate 125 . 88 
 
 MgO No change 1.40 
 
 Total 130.61 
 
 The percentage composition of this hydrate would be as follows: 
 
 Al 2 3 +Fe 2 03 = 1.21% 
 
 Ca(OH) 2 
 
 19 
 
In the same manner, the hydrate produced from the dolomitic 
 lime can be calculated. In this lime there is 61.27% of lime and this 
 amount would yield on hydration as follows: 
 56:74 = 61. 27:X X = 80.96 
 
 SiO 2 No change 1 . 74 parts 
 
 Al 2 O3+Fe 2 O3 No change .73 
 
 Ca(OH) 2 Changed to hydrate 80 . 96 
 
 MgO No change 36. 26 
 
 Total '" 
 
 The percentage composition of this hydrate would be as follows: 
 
 A , 2 3+ Fe 2 3 - .61 
 
 
 In the foregoing the attempt has been made to explain clearly and 
 simply the chemical changes which take place in the manufacture and 
 use of lime some knowledge of this subject is necessary for the manu- 
 facturer if the material is to be prepared in a proper manner. The user 
 of lime also should understand the action of burned lime if the material 
 is to be handled to the best advantage. 
 
 20 
 
CLASSIFICATION OF LIME 
 
 CHAPTER III 
 
 ORIGIN Limestone is the raw material from which lime is manufactured. 
 In general, limestones have been formed by accumulation of 
 remains of sea organisms, such as the foraminifera, corals and mollusks 
 at the bottom of the sea. These limestones sometime show the fossil 
 remains from which they were formed while in other instances all trace 
 of their organic origin has been destroyed. 
 
 DEFINITION OF The term "limestone" as used in the lime industry 
 LIMESTONE may be defined as a general term referring to that class 
 
 of rocks containing 80% or over of the carbonates of 
 calcium and magnesium, which, when calcined, give products which slake 
 upon the addition of water. Limestones are generally differentiated 
 geologically, based upon their different origin, texture and composition. 
 Depending upon their physical appearance, the most important varieties 
 are as follows: 
 
 CLASSES OF Marble Limestone having a coarse or fine crystalline 
 LIMESTONE structure which has been produced by heat and pressure. 
 Chalk A soft friable limestone composed of finely divided 
 shells consisting principally of those of the foraminifera. 
 Oolitic Limestone (Oolite) A limestone made up of small rounded 
 grains so named because of its supposed resemblance to fish-roe. 
 Marl A soft friable material made up of grains of carbonate of lime 
 generally found in lake basins. 
 
 COMPOSITION OF Depending upon their composition, limestones are 
 LIMESTONE generally distinguished as follows: 
 
 Argillaceous or clayey limestone, containing con- 
 siderable clay. 
 
 Arenaceous or silicious limestone, containing considerable silica or sand. 
 Conglomerate Limestone, containing large pebbles of lime-rock. 
 Dolomite, a double carbonate of calcium and magnesium containing 
 when pure 54.35% of calcium carbonate and 45.65% of magnesium 
 carbonate. 
 
 Magnesian Limestone, containing between 10 and 30% of magnesium 
 carbonate. 
 
 High Calcium Limestone, a limestone containing not more than 10% of 
 magnesium carbonate. 
 
 NOTE The preceding defiinitions are taken largely from the paper presented by 
 Irving Warner and the author before the National Lime Manufacturers' Association 
 in 1910. 
 
 21 
 
DEFINITION Lime may be defined as the product resulting from the 
 OF LIME calcination of a limestone consisting essentially of the car- 
 bonates of calcium and magnesium, which slakes upon the 
 addition of water. 
 
 Since all limes are made from limestone, it follows that a classi- 
 fication of lime might be introduced which would indicate the origin of 
 the lime or the kind of stone from which it was made. Following this 
 system, the term "Marble lime'* would indicate that the lime was pro- 
 duced from marble; " Argillaceous lime" one produced from a argill- 
 aceous limestone and the "Silicious lime" one produced from a silicious 
 limestone, etc. Such a classification, however, would have little practical 
 value for the building trades. A more rational classification is therefore 
 based upon the chemical composition of the stone and the form in which 
 the lime is brought into the market. 
 
 TYPES OF Classification of lime based upon the chemical composition: 
 LIME (a) High Calcium Lime Containing at least 90% of cal- 
 
 cium oxide. 
 
 (b) Calcium Lime Containing from 85% to 90% of calcium oxide. 
 
 (c) Magnesian Lime Containing from 85% to 90% of calcium and 
 magnesium oxides, 10% to 25% being magnesium oxide. 
 
 (d) High Magnesium Lime Containing not less than 85% of calcium 
 and magnesium oxide, not less than 25% being magnesium oxide. 
 
 (e) Hydraulic Lime Which contains so large a percentage of lime silicate, 
 aluminate or ferrate as to give the material the property of hardening 
 under water, but which at the same time contains so much free lime that 
 the burned mass will slake upon the addition of water. 
 
 BUILDING TRADES Classification of lime and lime products based 
 CLASSIFICATION upon the form in which they are supplied the 
 OF LIME trade: 
 
 (a) Run of Kiln Lime The product as it comes 
 from the kiln, without any sorting or further preparation. 
 
 (b) Selected Lump Lime A well burned lime which has been freed from 
 core, ashes and cinder by sorting. 
 
 (c) Ground or Pulverized Lime Lime which has been reduced in size to 
 pass a J^ inch screen. 
 
 (d) Hydrated Lime A dry flocculent powder resulting from the treat- 
 ment of quicklime with sufficient water to satisfy chemically all the 
 calcium oxide present. 
 
 The various kinds of lime mentioned under the chemical classifica- 
 tion may be brought into the market in any of the above four forms. 
 For example, hydrated lime may be prepared from a high calcium, 
 calcium, magnesian or high magnesian lime. 
 
 22 
 
CLASSIFICATION OF The terms fat and lean are often applied to 
 LIMES AS FAT, lime and refer only to the working qualities of 
 
 LEAN OR HYDRAULIC the paste and not to the chemical composition. 
 
 A fat or rich lime is a term employed by the 
 
 users of lime, to express smooth working qualities and great sand carry- 
 ing capacity. A lean or poor lime is the opposite of a fat lime. 
 
 Lieut. W. H. Wright in his book on Mortars published in 1845 
 classified limes as follows: "Lime which is used for building purposes 
 is rarely pure lime, but besides water and carbonic acid imbibed from 
 the atmosphere contains usually some foreign substances. These sub- 
 stances modify the properties of pure lime, and, when combined with 
 it in certain proportions, entirely change its nature. It will therefore 
 be convenient to arrange the limes employed in construction into four 
 different classes, 1st, the fat limes; 2nd, the poor or meager limes; 3rd> 
 the hydraulic limes and 4th, the hydraulic cements. 
 
 "The fat limes are more than doubled in volume during the process 
 of slaking, which is always attended with much heat. If converted 
 into paste and immersed in water, they w T ill remain of a soft consistency 
 forever * * * . Builders call them fat limes, because the paste, 
 which they form with water, is soft and unctuous to the touch. 
 
 "The poor or meager limes include all those which, in slaking, do 
 not undergo an increase of volume equal to twice their original bulk, 
 
 but exhibit, when immersed, the same qualities as the rich limes, * 
 
 * * 
 
 "The hydraulic limes possess the property of setting under water, 
 in periods of time varying from one to forty days after immersion, and 
 continue to harden more or less rapidly, according to the hydraulic 
 energy which they respectively possess. They all slake, but with diffi- 
 culty; the stronger kinds exhibiting few or none of the appearances 
 usually seen in fat lime during the slaking process, little or no vapor 
 being formed, and scarcely any heat disengaged; and they undergo an 
 increase of volume, in the inverse ratio of their hydraulic energy. 
 
 "The hydraulic cements differ from the limes, in not slaking at all 
 after calcination, unless they are previously pulverized; and they then 
 form a paste with water, without any perceptible disengagement of 
 heat, or augmentation of volume. They contain a large amount of the 
 hydraulic base or principle, and set under water in a much shorter time 
 than the limes require to set in air." 
 
 The classification of lime based upon the chemical composition and 
 the form in which the material is brought into the market is the most 
 concise and clear, and it is recommended that this classification be used. 
 
 23 
 
MANUFACTURE OF LIME 
 
 CHAPTER IV 
 
 LIME is produced by expelling the carbon dioxide contained in 
 limestone by means of heat. To accomplish this, it is necessary 
 to heat the stone to the temperature of decomposition and 
 further to supply sufficient heat to liberate the gas from the ston<VJMr4~ 
 scientific terms, to break the chemical bond between the calcium and 
 magnesium oxides and the carbon dioxide. It is not sufficient simply to 
 heat the stone to the point of decomposition, but it is necessary to hold 
 the stone at this temperature and to supply more heat in order to accom- 
 plish the disruption of the bond. This disruption does not take place 
 at once, but requires time; hence, the stone must be retained in the 
 burning zone long enough for the heat to accomplish its purpose. 
 
 Since it is necessary only to supply sufficient heat to the limestone 
 to obtain lime, the earliest methods of burning were very simple and 
 required but little skill. Perhaps the earliest method of burning was a 
 heap of stones on the ground with logs used as fuel. 
 
 TYPE OF These can be divided into two general classes as follows: 
 KILNS 1st Intermittent Kilns. 
 
 2nd Continuous Kilns. 
 
 POT KILN 1st Intermittent kilns, usually called "pot kilns," are 
 those in which each burning of a charge constitutes a 
 separate operation. The kiln is charged, burned, cooled, and then 
 drawn. After completing the cycle, the kiln is recharged for another 
 burning. Such a kiln often consists of a crude shaft excavated in the side 
 of a hill; the interior of the shaft being lined with larger stones of the 
 same material as those to be burned. At the bottom of the shaft, there 
 is a horizontal passage to the outside. At the place where the horizontal 
 passage meets the vertical shaft, an arch of limestone is made, and on 
 top of this, more limestone is placed until the shaft is completely filled. 
 A fire is then built under the arch, and the burning is continued until 
 the stone is thoroughly calcined. Page No. 25. 
 
 24 
 
POT KILN 
 An Early Form of Lime Kiln 
 
 FIELD KILN At a somewhat later date, kilns were built in the open 
 having vertical walls of masonry of a circular or square 
 section but in other ways resembled the shaft in the side of the hill. These 
 early types of shaft kilns are still to be found scattered throughout the 
 country. A description of such a kiln given by Chas. T. Jackson, in the 
 Third Annual Report on the Geology of Maine, published in 1839, states 
 that this type of kiln was usually "built of refractory rock, lined with 
 clay and laid outside with mortar 15 ft. wide 15 ft. high 5 ft. back 
 Arches middle, 5 ft. high side arches, 3 j/2 ft. high. This kiln is the form 
 commonly used at Thomaston, and the lime is burned by means of wood 
 fuel, 30 cords of wood being required to burn the charge of rock. The 
 operations are divided into four turns, and for three or four days and 
 nights the fire is kept unremittently in action." Page No. 26. 
 
 25 
 
FIELD KILN 
 Described by Jackson in 1839 
 
 Such a kiln would produce about 300 casks, or 45 tons of lime at 
 a burning. Jackson further states that similar kilns were constructed 
 of a circular form. 
 
 This type of kiln commonly called a Pot Kiln can never be economical 
 since there is an enormous loss of heat at each burning owing to the quan- 
 tity of fuel required to raise the contents of the kiln and the surrounding 
 thick stone walls to the necessary temperature each time the kiln is 
 charged. Further, the stone nearest the arch is liable to become over- 
 burned before the top portion of the charge is calcined. 
 
 CONTINUOUS This class can be subdivided as follows: 
 KILNS (a) Vertical kilns, mixed feed. 
 
 (b) Vertical kilns, separate feed. 
 
 (c) Ring, or chamber, kilns. 
 
 (d) Rotary kilns. 
 
 DRAW KILN (a) Vertical Kiln, Mixed Feed This type of kiln, gener- 
 ally called a draw kiln, is similar to the pot kiln; the lime- 
 stone and fuel are charged at the top in alternate layers, and the burning 
 proceeds from a point near the top, the lime being withdrawn at the 
 bottom. The advantage of this type of kiln is that it is cheap to con- 
 struct, and is economical in fuel. Its disadvantage is the discoloration 
 and contamination of the burned lime by the ashes from the fuel; also 
 the ashes combine with the lime, producing lumps which prevent thor- 
 ough and satisfactory slaking. An early kiln of this type is illustrated 
 herewith; this kiln was one in use at Thomaston, Maine, in 1838, an- 
 thracite coal screenings being used as fuel. Page No. 27. 
 
 26 
 
DRAW KILN 
 Described by Jackson in 1839 
 
 7 
 
VERTICAL STEEL KILN 
 A Modern Steel Encased Flame Kiln. 
 
VERTICAL STEEL KILN WITH STACK 
 A Modern Steel Encased Flame Kiln with Stack to Increase the Draught 
 
 29 
 
The Aalborg or Schofer kiln, neither of which has been much used 
 in this country, illustrates the best development of this class of kiln. The 
 stone is charged in at the top, while the fuel is fed into chutes, which 
 join the main shaft of the kiln some distance below the top. Such kilns 
 are very economical in fuel, but the lime is contaminated with the ashes. 
 
 VERTICAL (b) Vertical Kiln with Separate Feed This is the most 
 
 STEEL KILN common type of kiln at present used in this country. It 
 consists of a vertical shaft built of masonry and lined 
 with fire brick, having a round section. It is equipped with two or more 
 fire boxes like Dutch ovens for burning the fuel which are built into the 
 side of the kiln near the bottom so that the fuel does not come in contact 
 with the lime. Its advantages are that any kind of fuel can be used in- 
 cluding coal, wood, gas or oil, and the lime produced is clean because it 
 does not come in contact with the burning fuel. Other things being equal, 
 the fuel economy would not be so great as in class (a) above. Pages 
 No. 28 and 29. 
 
 RING KILN (c) Ring or Chamber Kiln This kiln is generally known as 
 the Hoffman Kiln, and it has been extensively used for 
 burning brick, cement and lime in Europe. It has been but little used in 
 this country for burning lime, although there are now old kilns of this 
 type at Riverton, Va. and Kelley Island, Ohio. It is very economical in 
 fuel, producing a good grade of lime, but the labor cost of operating is 
 excessive. 
 
 ROTARY KILN (d) Rotary Kiln This kiln is the same as that commonly 
 employed for burning Portland cement, except that 
 gaseous fuel is used. The kiln is very economical both as to fuel consump- 
 tion, and the cost of labor to operate. It has, however, the disadvantage 
 that limestone fed to it must be crushed rather finely, and hence the 
 burned product is also fine. 
 
 FUEL The use of kilns with separate fire boxes was largely brought 
 about by the high cost of wood and the necessity of employing a 
 cheaper fuel, such as coal. As long as wood was plentiful and cheap, it 
 was the fuel most used for burning lime, and the simpler type of kiln 
 was practical. With the increasing scarcity of wood, most lime plants 
 have been forced to adopt the use of coal, and the use of coal has in turn 
 necessitated the adoption of a different and more complicated type of 
 kiln. If an old lime burner is asked "what is the best fuel for the burn- 
 ing of lime," his answer will be "wood," since wood produces a long, 
 mild flame. Unless the combustion is carefully controlled when coal 
 alone is used, there is undoubtedly too short and intense a flame to pro- 
 duce the best quality of lime. 
 
 SO 
 
COAL Methods of controlling the combustion have been devised so that 
 there is obtained from coal the desired long, mild flame, which 
 produces a good grade of lime. The most common of these methods is 
 to introduce steam below the grates of the fire boxes. Another device is 
 that known as the Eldred process. By this process a portion of the gas is 
 removed from the kiln near the top by means of a fan, and this gas is 
 then mixed with air and introduced beneath the grates of the furnace. 
 This process accomplishes a dilution of the air by mixing it with the spent 
 gas from the top of the kiln, and a good, long flame of low intensity is 
 produced. This flame is not apt to overheat the lime nor cause over- 
 burning. 
 
 PRODUCER The most recent advance in connection with the use of coal 
 GAS is its gasification in producers, and the use of this gas to 
 
 burn the lime. Producer gas gives a flame of low intensity 
 and great volume which resembles closely the flame of burning wood. 
 The producer gas method of burning requires more careful regulation and 
 more skillful management than the other methods. A number of pro- 
 ducer gas installations have proved failures because of the lack of knowl- 
 edge as to how they should be installed and lack of scientific manage- 
 ment. Pages No. 32 and 33. 
 
 It will thus be seen that from the simple kilns used by our fore- 
 fathers in which wood was used as a fuel, we have advanced to a more 
 complex type of kiln which resembles somewhat an iron blast furnace, 
 and in which producer gas is used as fuel. With each step in the advance, 
 the amount of capital required to construct the kiln has greatly in- 
 creased. 
 
VERTICAL PRODUCER GAS KILN 
 A Modern Producer Gas Fired Lime Kiln 
 
SLAKING LIME 
 
 CHAPTER V 
 
 CHEMICAL CHANGE The term "slaking" refers to the change produced 
 
 DURING SLAKING when lime is treated with water. As is well known, 
 
 PROCESS a violent action occurs when water is added to 
 
 lime: the lumps break up, heat is generated, and 
 
 a product is formed which has an entirely different character than the 
 original quick lime. This phenomenon indicates that a chemical reaction 
 has taken place. In this chemical change the calcium oxide (lime) has 
 united with water forming a new compound, calcium hydroxide 
 (slaked lime). The chemistry of this change has been fully explained 
 in the chapter devoted to the "Chemistry of Lime." 
 
 QUICK OR SLOW In order to render lime as it comes from the kiln suit- 
 SLAKING LIMES able for use in mortar it is necessary to slake it. This 
 is generally accomplished by adding sufficient water to 
 the lime to produce a thick paste. The various kinds of lime mentioned 
 under the chemical classification of lime act in very different manners 
 when treated with water. The high calcium limes are quick slaking and 
 give off the greater amount of heat because these limes consist principally 
 of calcium oxide, this being the material which, by combining with water, 
 generates the heat. As the amount of impurities (silica, alumina and 
 iron oxide), increases the lime contains less calcium oxide and is therefore 
 slower slaking. Such slow slaking limes are generally termed "lean" 
 limes. 
 
 The dolomitic quick limes are slower slaking and generate less heat 
 because they contain less calcium oxide; a part of the calcium oxide 
 being replaced by magnesium oxide which does not combine with water 
 under the ordinary conditions of slaking. In case the dolomitic limes 
 contain impurities, such as silica, alumina and iron oxide, they are 
 rendered slower slaking for the same reason as given for the high cal- 
 cium lime. 
 
 METHOD OF The ordinary method of slaking quick lime is to add suf- 
 SLAKING ficient water to produce a thick paste after the reaction of 
 
 slaking is completed. In this method of slaking sufficient 
 water should be used in order that it may come in contact with all parts 
 of the lime. If insufficient water is used some parts of the mass of lime 
 become dry and are " burned" in slaking. "Burned" lime works 
 
 34 
 
tough and non-plastic in the mortar. If an excess of water is used, the 
 slaking proceeds slowly and the resulting paste is thin and watery. 
 Such lime paste is spoken of as "drowned." 
 
 4 
 
 Since various kinds of lime differ greatly in their behavior in slak- 
 ing, some requiring more water and some a longer time to become re- 
 duced to a proper paste, it is necessary to exercise great care in slaking. 
 A quick slaking lime will require a large amount of water and this must 
 be added quickly, also the lime must be turned over rapidly so that the 
 water has access to all parts and no "burning" takes place during slak- 
 ing. On the contrary, the slower slaking limes, such as the dolomites, 
 require less water, and care is necessary to see that these limes are not 
 "drowned." In a treatise of this kind, it is impossible to give detailed 
 instructions as to the best method of slaking the individual limes since 
 each lime possesses its own characteristics, particularly as to its behavior 
 in slaking. Too often the slaking is left to inefficient and ignorant 
 labor with the result that the mass of lime is not thoroughly slaked, 
 being either "burned" or "drowned." 
 
 QUANTITY OF WATER 
 REQUIRED FOR SLAKING 
 
 Some recent tests made by Cloyd M. Chap- 
 man* illustrate very clearly the variation in 
 
 the amount of water required to slake lime to 
 
 a paste. In making this test great care was exercised to bring the paste 
 to a standard uniform consistency. 
 
 TABLE No. 3 RESULTS OF LIME TESTS 
 HIGH CALCIUM LIME 
 
 Sample No. 
 Source 
 
 117 
 York 
 Pa. 
 
 114 
 Farnum 
 Mass. 
 
 116 
 Farnum 
 Mass. 
 
 118 
 Rock- 
 land 
 Me. 
 
 120 
 West 
 Stock- 
 bridge 
 Mass. 
 
 113 
 York 
 Pa. 
 
 119 
 Adams 
 Mass. 
 
 115 
 
 West 
 Stock- 
 bridge 
 
 Mass. 
 
 
 Marked 
 
 Lump 
 Lime 
 
 Lump 
 Lime 
 
 Lump 
 Lime 
 
 Lump 
 Lime 
 
 Lump 
 Lime 
 
 Lump 
 Lime 
 
 Granu- 
 lar 
 Lime 
 
 Lump 
 Lime 
 
 Av. 
 
 Analysis CaO 
 MgO 
 Si0 2 
 R 2 O 3 
 Gals, water per 
 bbl. to make putty 
 Lbs. lime in 1 cu. 
 ft. putty 
 Weight 1 cu. ft. 
 putty in Ibs. 
 
 99.04 
 0.65 
 0.10 
 0.12 
 
 29.4 
 43.1 
 95.2 
 
 98.91 
 
 98.91 
 
 96.81 
 1.27 
 0.42 
 0.88 
 
 30.5 
 44.6 
 100.1 
 
 95.23 
 0.71 
 3.46 
 0.60 
 
 32.4 
 41.2 
 96.7 
 
 95.00 
 
 94.87 
 0.84 
 2.05 
 1.86 
 
 32.9 
 
 38.6 
 91.5 
 
 84.31 
 5.84 
 3.54 
 2.00 
 
 28.3 
 45.2 
 97.8 
 
 95.38 
 1.16 
 
 1.38 
 0.77 
 
 30.9 
 41.4 
 94.4 
 
 0.73 
 0.36 
 
 32.2 
 
 38.7 
 93.0 
 
 0.73 
 0.36 
 
 32.7 
 38.0 
 89.3 
 
 
 0.36 
 29.1 
 41.8 
 92.2 
 
 *Data on Lime Putty and Cream of Lime by Cloyd M. 
 Concrete Institute, November and December, 1914. 
 
 Chapman, Journal of American 
 
 35 
 
TABLE No. 3 RESULTS OF LIME TESTS, Cont'd 
 DOLOMITIC LIME 
 
 Sample No. 
 Source 
 
 121 
 Dover 
 Plains 
 N. Y. 
 
 124 
 
 Knicker- 
 bocker 
 Pa. 
 
 
 Marked 
 
 Dutchess 
 County Lime 
 
 Lump Lime 
 
 Average 
 
 Analysis CaO 
 MgO 
 Si0 2 
 R 2 3 
 Gals, water per bbl. to make putty 
 Lbs. lime in cu. ft. putty 
 Weight 1 cu. ft. putty in Ibs. 
 
 56.46 
 38.54 
 1.58 
 1.60 
 25.3 
 50.6 
 102.4 
 
 56.99 
 40.11 
 2.11 
 0.79 
 22.8 
 56.5 
 109.0 
 
 56.72 
 39.32 
 1.85 
 1.14 
 24.0 
 53.5 
 105.7 
 
 An inspection of Table No. 3 brings out the following features: 
 
 (1) The amount of water required to make putty by the dolomitic 
 limes tested is about 20 per cent less than for the high calcium limes. 
 
 (2) The amount of water required to slake and reduce to a putty 
 one barrel of high calcium lime is a variable quantity and for the samples 
 tested ranges from 28.3 to 32.9 gallons. The average is about 31 gallons 
 and for average conditions this figure may be close enough for most 
 purposes. In the cases of the dolomitic lime this quantity of water is 
 considerably less and averaged for the two samples tested 24 gallons. 
 
 (3) The weight of high calcium lime in a cu. ft. of putty ranged 
 from 38.6 to 45.2 Ibs. and averaged 41.4 Ibs., which figure is probably 
 a satisfactory one to use on the job. For dolomitic limes the average 
 was 53.5 Ibs. 
 
 (4) The weight of 1 cu. ft. of putty made from high calcium lime 
 varied from 89.3 to 100.1 Ibs. and averaged 94.4 Ibs. and for dolomitic 
 limes the average was 105.7 Ibs. 
 
 In order to make this point more clear the table has been recal- 
 culated, allowance being made for the amount of water which enters 
 into chemical combination with the lime. 
 
 HIGH CALCIUM LIME 
 
 Sample No. 
 
 117 
 
 114 
 
 116 
 
 118 
 
 120 
 
 113 
 
 119 
 
 115 
 
 Av. 
 
 Lbs. CaO in bbl. 
 
 183.2 
 
 182.9 
 
 182.9 
 
 179.1 
 
 176.2 
 
 175.7 
 
 175.5 
 
 156.0 
 
 
 (185 Ibs. lime net) 
 
 
 
 
 
 
 
 
 
 
 Water chemically 
 
 
 
 
 
 
 
 
 
 
 combined with 
 
 
 
 
 
 
 
 
 
 
 lime, Ibs. 
 
 58.8 
 
 58.7 
 
 58.7 
 
 57.5 
 
 56.6 
 
 56.5 
 
 56.4 
 
 50.1 
 
 
 Free water in 
 
 
 
 
 
 
 
 
 
 
 paste, Ibs. 
 
 186.2 
 
 220.7 
 
 214.9 
 
 196.7 
 
 213.5 
 
 186.1 
 
 217.8 
 
 137.0 
 
 
 Free water in paste, salt 
 
 22.3 
 
 26.5 
 
 25.8 
 
 23.6 
 
 25.6 
 
 22.3 
 
 26.1 
 
 16.4 
 
 23.6 
 
DOLOMITIC LIME 
 
 Sample No. 
 
 121 
 
 124 
 
 Av. 
 
 Lbs. CaO in bbls. (185 Ibs.lime net) 
 Water chemically combined with 
 lime, Ibs. 
 Free water in paste, Ibs. 
 Free water in paste, gals. 
 
 104.4 
 
 33.5 
 177.2 
 21.2 
 
 104.9 
 
 33.7 
 146.2 
 17.5 
 
 19.3 
 
 The first line gives the number of pounds of calcium oxide in a 
 barrel of lime containing 185 pounds net. 
 
 The second line gives the pounds of water chemically combined with 
 the above amount of calcium oxide. 
 
 Line three gives the pounds of free water in the paste. 
 
 Line four gives the gallons of free water in the paste. 
 
 An inspection of this table shows that the amount of free water in 
 a paste made from high calcium lime varies from 16.4 gallons to 26.5 
 gallons with an average amount of 23.6 gallons. 
 
 The amount of free water in a paste made from dolomitic lime varies 
 from 21.2 gallons to 17.5 gallons with an average of 19.3 gallons. 
 
 The above two tables illustrate very clearly the great variation in the 
 quantity of water required to reduce various limes to a workable paste. 
 Because of this great variation, it is very dLUcult to determine in advance 
 the amount of lime which is present in a mortar made from lump lime. 
 
 LIME "BURNED" It is a well known fact that w T hen quick lime is 
 DURING SLAKING slaked to a paste, if insufficient water is used the 
 resulting paste is not so plastic and works short. 
 This condition is generally spoken of as "burning" in slaking. Until 
 very recently, no scientific reason was known for this "burning" of lime 
 during slaking. W. E. Emley, of the U. S. Bureau of Standards, in a 
 paper presented before the National Lime Manufacturers' Association in 
 February 1914, gave the first explanation of this "burning" during slak- 
 ing with which the writer is familiar. According to Emley, when in- 
 sufficient water is used in slaking, the temperature of the mass is raised 
 considerably above the boiling point of water, and at this elevated tem- 
 perature a compound is formed which has different characteristics than 
 ordinary calcium hydroxide. For convenience it may be called lime 
 "burned" during slaking. This "burned" compound differs chemically 
 from calcium hydroxide in the rapidity with which it absorbs carbon dioxide 
 from the air, this reaction being so rapid that it is practically impossible 
 to weigh the material on the ordinary chemical balance. Physically it 
 differs from both lime and hydrate in that it feels gritty and has a slightly 
 yellow color. Under the microscope it differs optically from both lime 
 
 37 
 
and hydrate. These chemical and physical differences show that the 
 compound formed by "burning" in slaking is neither lime nor hydrate 
 but a new chemical compound. Since the material has not been isolated 
 in a pure state it is therefore impossible to assign to it a definite formula; 
 in all probability it is an oxy-hydrate. It has been shown that a basic 
 carbonate of lime having the formula 2CaO . CO 2 can be formed, also the 
 corresponding hydrate is known Ca(OH) 2 . CaCO 3 . Arguing from these 
 compounds, the probable formula for the so called oxy-hydrate would 
 be CaO.Ca(OH) 2 . 
 
 AGING LIME The danger of "burning" in slaking is much greater with 
 PASTE high calcium limes since these generate the greater amount 
 
 of heat, and it is therefore necessary to employ a large 
 excess of water and to see that all the lime comes in contact with water. 
 This excess of water lowers the temperature both by absorbing the heat 
 and by evaporation. 
 
 Slaking is a chemical process and time is required to complete the 
 action; hence, it is necessary to allow the paste to age for some time to 
 be assured of complete slaking. All lime contains some over-burned 
 particles, or particles of lime which have united chemically with the 
 silica or clay in the limestone, and these particles are extremely slow 
 slaking, often requiring days and weeks to become thoroughly satis- 
 fied with water. Our forefathers recognized this fact and always allowed 
 the lime paste to age for weeks, and often months, before using. 
 
 The necessity of aging lime paste before using was recognized by 
 the Romans. Vitruvius gives the following directions for the prepara- 
 tion of lime paste to be used in plastering.* "This will be all right if the 
 best lime, taken in lumps, is slaked a good while before it is to be used, 
 so that, if any lump has not been burned long enough in the kiln, it will 
 be forced to throw off its heat during the long course of slaking in the 
 water, and will thus be thoroughly burned to the same consistency. When 
 it is taken not thoroughly slaked but fresh, it has little crude bits con- 
 cealed in it, and so, when applied, it blisters. When such bits complete 
 their slaking after they are on the building, they break up and spoil the 
 smooth polish of the stucco. 
 
 "But when the proper attention has been paid to the slaking, and 
 greater pains have thus been employed in the preparation for the work> 
 take a hoe, and apply it to the slaked lime in the mortar bed just as you 
 hew wood. If it sticks to the hoe in bits, the lime is not yet tempered; 
 and when the iron is drawn out dry and clean, it will show that the lime 
 is weak and thirsty; but when the lime is rich and properly slaked, it will 
 stick to the tool like glue, proving that it is completely tempered." 
 
 "Vitruvius, translated by Morris Hicky Mo.-gan, Cambridge, Mass., 1914, page 204. 
 
 38 
 
The art of preparing lime mortar of the finest quality has survived 
 in Italy to this day. *" So late as 1851 an English architect, when sketch- 
 ing in the Campo Santo at Pisa, found a plasterer busy in lovingly repair- 
 ing portions of its old plaster work, which time and neglect had treated 
 badly, and to whom he applied himself to learn the nature of the lime 
 he used. So soft and free from caustic qualities was it that the painter 
 could work on it in true fresco painting a few days or hours after it was 
 repaired, and the modeler used it like clay. But until the very day the 
 architect was leaving no definite information could he extract. At last, 
 at a farewell dinner, when a bottle of wine had softened the way to the 
 old man's heart, the plasterer exclaimed, 'And now, signor^I will show 
 you my secret!* And immediately rising from the table, the two went 
 off into the back streets of the town, when, taking a key from his pocket, 
 the old man unlocked a door, and the two descended into a large vaulted 
 basement, the remnant of an old palace. There amongst the planks and 
 barrows, the architect dimly saw a row of large vats or barrels. Going 
 to one of them, the old man tapped it with his key; it gave a hollow 
 sound until the key nearly reached the bottom. * There, signor! There 
 is my grandfather! He is nearly done for.' Proceeding to the next, 
 he repeated the action, saying, 'There, signor, there is my father! 
 There is half of him left.' The next barrel was nearly full. 'That's me!' 
 exclaimed he; and at the last barrel he chuckled at finding it more than 
 half full; 'That's for the little ones, signor!' Astonished at this barely 
 understood explanation, the architect learned that it was the custom of 
 the old plasterers, whose trade descended from father to son from many 
 successive generations, to carefully preserve any fine white lime produced 
 by burning fragments of pure statuary, and to each fill a barrel for his 
 successors. This they turned over from time to time, and let it air- 
 slake in the moist air of the vault, and so provide pure old lime for the 
 future by which to preserve and repair the old works they venerated. 
 After inquiries showed that this was a common practice in many an old 
 town, and thus the value of old air-slaked lime, such as had been written 
 about eighteen hundred years before, was preserved as a secret of the 
 trade in Italy, whilst the rest of Europe was advocating the exclusive 
 use of newly burnt and hot slaked lime." 
 
 NECESSITY FOR If a good, sound, smooth working lime paste is to be 
 
 HYDRATED LIME made from lump lime, it is absolutely necessary that 
 
 the lime be slaked some considerable time before using. 
 
 Compare the method of slaking recommended by Vitruvius and that 
 
 of the skilled Italian plasterer with the modern method of slaking the 
 
 lime in the middle of a ring of sand and almost immediately hoeing in 
 
 *Hodgson, Concrete, Cement, Mortar, Plaster and Stucco, pages 22 to 25. 
 
the sand. In the present practice more often than not, the plaster is 
 placed on the wall or the mortar laid between the bricks within a few 
 hours. Such mortar must contain free lime that has not had time or 
 opportunity to slake. This lime later takes up water causing the mortar 
 to be crumbly or the plaster to crack and pop. 
 
 In spite of improvements in the method of producing lime with 
 better and more economical kilns, the material is brought into the mar- 
 ket in the same manner as it was centuries ago. Further, the method 
 of slaking lime has changed only for the worse, in that our rapid modern 
 practice does not admit of the slow action of slaking lime thoroughly 
 on the operation. 
 
 The only improvement in the form of the merchantable lime, known 
 to the author, is that of hydrated lime. This will be dealt with in the 
 next chapter. 
 
 40 
 
MANUFACTURE OF HYDRATED LIME 
 
 CHAPTER VI 
 
 WITHIN recent years a method has been introduced of treating 
 lime with water in a suitable apparatus in which the lime com- 
 bines with sufficient water to satisfy the chemical requirements 
 of the calcium oxide forming a dry, finely divided flour, the so called 
 Hydrated Lime. Hydrated lime can be defined as the dry fiocculent powder 
 resulting from the treatment of quick lime with sufficient water to satisfy the 
 calcium oxide. This material comes into the market in bags or other 
 convenient packages and is ready for use requiring only gauging with 
 water and mixing with sand in much the same manner as cement is 
 used. The fact that lime could be slaked to the form of a dry powder 
 has long been known, and three methods have been used in the past to 
 produce this powder. 
 
 METHODS OF 1. Lime, in comparatively small pieces about the size 
 DRY SLAKING of an egg, is placed in a basket and immersed in water 
 for a minute or two until hydration has commenced, 
 when it is withdrawn. The wet lime is generally put in heaps or silos in 
 order to conserve the heat and prevent the escape of the vapor. The 
 material swells, cracks and becomes reduced to a dry powder. 
 
 2. Lumps of lime are placed in a heap and wetted at intervals so 
 that the mass is equally moistened throughout. The slaking proceeds 
 as in the first instance. 
 
 3. Small pieces of lime are exposed to the air for a number of 
 months. The material absorbs both water and carbon dioxide from the 
 atmosphere, falling to a dry powder. The powdered form consists of a 
 hydrated sub-carbonate of lime containing about 10% to 11% of water. 
 
 These methods of dry slaking lime are crude, and unless the greatest 
 care is exercised, the resulting dry product will contain particles of un- 
 slaked lime. Further, the hydrates produced by these methods gen- 
 erally work short and possess poor sand carrying capacities; in fact, 
 hydrated lime produced by any of the above methods is only suitable 
 for use on the soil, and such hydrate should not be confounded with 
 hydrated lime manufactured by modern methods. 
 
 41 
 
MODERN METHODS The modern method of manufacturing hydrated 
 
 OF HYDRATING lime depends upon the addition of an exact amount 
 
 of water to a pre-determined exact amount of lime. 
 
 By no other method is it possible to produce a hydrate which will contain 
 sufficient combined water to satisfy the demands of the calcium oxide 
 present. It is important that all the calcium oxide be in combination 
 with water, otherwise the hydrate will be unsound and unsuitable for 
 many uses. This point will be insisted upon in any specifications that 
 may be drawn for hydrated lime to be used in the building trade. It is 
 vital for each manufacturer to recognize the fact that the formation of 
 hydrated lime involves a chemical change, requiring the presence of 
 definite amounts of lime and water. Since the process is chemical, it 
 requires the same careful supervision as any other chemical process, 
 such as the manufacture of Portland cement. 
 
 PIERCE PROCESS The first commercial process used for preparing hy- 
 drated lime in this country was the so-called " Pierce " 
 Process. This consisted in slaking the lime to a wet paste, then drying the 
 paste so as to expell all the excess moisture over and above that needed 
 for the chemical requirements, thereby reducing the material to a form 
 that could be ground. If the process was carefully carried out, a good 
 grade of hydrated lime was produced. This method has been abandoned 
 owing to the excessive cost of manufacture. 
 
 DODGE PROCESS The second method employed was the so-called 
 "Dodge" Process. This process consisted first in 
 grinding the lime so as to pass a 26 mesh sieve, second in treating a 
 weighed amount of the ground lime with sufficient water thoroughly to 
 satisfy the calcium oxide present and produce a dry hydrate, third the 
 dry hydrate was sifted through fine silk cloth. A description of this 
 method is given in the "Engineering News," Vol. 50, Pages 177 to 179, 
 August 27, 1903, by S. Y. Brigham. In this article it is stated that on 
 the average high calcium limes containing 97% of calcium oxide require 
 about 55 pounds of water to 100 pounds of lime, while dolomitic limes 
 require only 36 pounds of water to 100 pounds of lime to produce a good 
 hydrate. 
 
 From these two pioneer processes have been evolved, during the 
 last fifteen years, the methods described below which are in use at the 
 present time. 
 
 CLYDE PROCESS A weighed quantity of ground lime is fed from a 
 hopper directly into a large horizontal pan. This pan 
 is so mounted that it can be rotated around its vertical axis, and there are 
 a series of plows arranged to turn over and mix the material in the pan. 
 To the weighed amount of lime a pre-determined quantity of water is 
 
 42 
 
added and the whole mass agitated by revolving the pan. When all the 
 water needed chemically, has been taken up, and the excess driven off 
 as steam, the hydrated lime is dumped through an opening in the 
 centre of the pan. It is customary to take the hydrate directly from 
 the pan, and store it in bins in order to age the product. The dry 
 hydrate from the bins is either screened or graded by means of air 
 separation. 
 
 CLYDE HYDRATOR 
 
 REANEY PROCESS A weighed amount of the lime is introduced into the 
 upper end of a cylinder, which is slightly inclined from 
 the horizontal. A sufficient amount of water is added, and the material 
 agitated by revolving the cylinder. Inside of the cylinder there are a 
 series of encircling rings, which act as dams to retard the flow of the 
 lime toward the discharge end. The lighter particles of the hydrate 
 rise and pass over the retarding rings while the heavier, unhydrated 
 particles are retained until the hydration is complete. The lower or 
 discharge end of the cylinder is encircled with a tapering screen; the fine 
 hydrated particles pass through this screen, and are removed. The 
 coarser particles which pass over the screen, are eitner thrown away or 
 returned to the feed end of the hydrator for further treatment. 
 
 KRITZER PROCESS The cracked or ground lime and water are separately 
 fed into the upper of a series of enclosed cylinders 
 
 (generally 4 or 6) mounted one on top of the other. The amount of 
 lime is controlled by a screw feeding device and the quantity of water is 
 proportioned by a needle valve. The lime and water are propelled 
 throughout the series of cylinders by means of paddles mounted on a 
 shaft extending through each cylinder; these shafts being rotated by gear- 
 ing on the outside. Both materials are thus carried through the whole 
 series of from four to six cylinders, and the product is discharged from 
 
 43 
 
KRITZEK HYDRATOR 
 
the lower or last cylinder thoroughly hydrated. The machine is also 
 provided with a stack on the upper cylinder, and openings in the lower 
 cylinder, thus a draft is produced through the cylinders in the opposite 
 
 direction to the travel of the lime. 
 
 ) 
 
 LAUMAN PROCESS The cracked lime is fed directly into an inclined 
 stationary cylinder; within this cylinder are paddles 
 
 carried on a shaft which feed the lime forward by their revolutions. The 
 water is added through a pipe in the upper end of the cylinder. As the 
 material is gradually fed forward it becomes mixed with w^ater and the 
 hydration takes place. The quality of the hydrate is judged by observ- 
 ing the material discharged from the cylinder. 
 
 These methods are in commercial use today and a good grade of 
 hydrate can be produced by any of the methods provided sufficient care 
 is taken to assure the addition of the correct amount of water and suf- 
 ficient time is allowed to form a sound hydrate. It is the general custom 
 either to screen the hydrate or to pass it through an air separating system 
 in order to remove particles of unhydrated lime, core and other impurities. 
 It is further important that the heat generated by the action of the lime 
 and water, be removed as rapidly as possible in order to keep the tem- 
 perature of hydration below the point at which the lime "burns" in 
 slaking. 
 
 IMPORTANT FEATURES In any method of hydrating lime an excess of 
 IN HYDRATING water is used over and above that required to 
 
 combine chemically with the lime. This excess 
 
 water is driven off as steam by the heat generated in slaking. The 
 quantity of water required is subject to wide variations, since it is de- 
 pendent upon a number of conditions, such as the temperature of the 
 water, lime and the atmosphere. If too little water is used, some particles 
 of lime will not have access to w r ater and these will not slake but will 
 be present in the finished hydrate, causing it to be unsound. Also too 
 little water results in the production of a hydrate which works short, 
 due to its having been "burned" in slaking. Too much water results in 
 a damp or wet hydrate, which is difficult to handle. The addition of the 
 correct amount of water requires the most careful supervision of any of 
 the operations of hydration if a good grade of hydrate is to be produced. 
 This part of the operation must be carefully controlled and be subjected 
 to checks from day to day. 
 
PROPERTIES OF HYDRATED LIME 
 
 CHAPTER VII 
 
 WATER CONTENT IN 
 HYDRATED LIME 
 
 Hydrated lime is a fine dry powder consisting 
 essentially of calcium hydrate and magnesium 
 oxide. The amount of combined water contained 
 
 in the hydrate varies directly as the calcium oxide content. Since cal- 
 cium oxide is the only compound present in lime which possesses the prop- 
 erty of combining with water, it follows that the greater the amount of 
 calcium oxide present in the lime, the greater will be the amount of water 
 required to combine with it. A more complete explanation of this fact 
 has been given in the chapter devoted to the Chemistry of Lime. 
 This is illustrated by the table given below: 
 
 Percent of calcium oxide Percent of calcium oxide 
 in original lime in hydrate 
 
 100 (a) 75.675 
 
 95 (b) 72.78 
 
 58.34 (c) 49.12 
 
 52 (d) 44.55 
 
 (a) Pure high calcium lime 
 (b) High calcium lime 5% impurities 
 (c) Pure dolomitic lime 
 (d) Impure dolomitic lime 
 
 Pure high calcium hydrate contains 24.32% of combined water, 
 while a pure dolomitic hydrate contains only 15.78%. As the amount of 
 impurities (silica and clay) increases, the amount of combined water 
 decreases. This may be seen by comparing (b) with (a) and (d) with 
 (c) in the above table. 
 
 CHEMICAL COMPOSITION OF The chemical compositions of various com- 
 VARIOUS HYDRATED LIMES mercial hydrated limes are given below: 
 
 Percent of water 
 required in hydrate 
 
 24.325 
 23.08 
 15.78 
 14.33 
 
 No. 
 
 1* 
 
 2* 
 
 3* 
 
 4* 
 
 5** 
 
 6* 
 
 7* 
 
 Silica 
 Alumina 
 Iron Oxide 
 Lime 
 Magnesia 
 Carbon Dioxide 
 Water 
 
 .42 
 
 !si 
 
 72.25 
 1.47 
 .57 
 
 24.98 
 
 .97 
 .29 
 .33 
 69.63 
 4.11 
 1.88 
 22.56 
 
 .95 
 .50 
 .51 
 71.66 
 .36 
 1.80 
 23.81 
 
 1.23 
 .42 
 
 .18 
 71.22 
 1.88 
 1.37 
 23.76 
 
 .96 
 .63 
 .13 
 73.45 
 .58 
 .69 
 23.97 
 
 3.05 
 .20 
 .30 
 48.76 
 30.04 
 .92 
 16.32 
 
 .24 
 
 .22 
 .06 
 52.27 
 28.96 
 
 16]79 
 
 73.72 73.74 72.02 73.10 74.03 78.80 81.23 
 
 Combined Oxides ) 
 
 CaO+MgO (Calculated) f 
 
 1 Maine 3 Pennsylvania 5 Washington 7 Ohio 
 
 2 New Jersey 4 Alabama 6 Michigan 
 
 Numbers 1, 2, 3, 4 and 5 represent high calcium hydrate. 
 
 Numbers 6 and 7 represent dolomitic hydrate. 
 
 *Analyses from Technologic Paper No. 16, Manufacture of Lime, Bureau of Standards. 
 ** Analysis by Author. 
 
 46 
 
PHYSICAL AND CHEMICAL In 1909 the author gave a table showing the 
 CHARACTERISTICS most important chemical and physical char- 
 
 acteristics of hydrated lime to the National 
 Lime Manufacturers' Association. This table is here reproduced. 
 
 DOLOMITIC HYDRATES 
 
 HIGH CALCIUM 
 HYDRATES 
 
 1 Weight per cu. ft. loose 
 2 Weight per cu. ft. shaken 
 3 Specific Gravity 
 4 Residue Insoluble in hydro- 
 chloric acid 
 5 Moisture 
 6 Combined water 
 7 Carbon Dioxide 
 8 Available Oxide 
 
 30.40 31.72 37.20 36.30 
 36.40 36.23 42.40 45.10 
 2.50 2.53 2.41 2.50 
 
 .40% .40% .24% .28% 
 .30 .00 .35 .00 
 17.22 15.88 18.07 17.29 
 .75 .30 .41 .17 
 80.38 83.02 80.47 82.03 
 
 35.70 35.80 
 41.20 45.30 
 2.16 2.07 
 
 .25% .33% 
 .00 .00 
 24.52 24.37 
 .54 .15 
 74.00 74.96 
 
 Referring to the table, the horizontal line 1 gives the weight per 
 cubic foot, loose. 
 
 Line No. 2 gives the weight per cubic foot, shaken. 
 
 Line No. 3 gives the specific gravity this is obtained by dividing the 
 weight of the substance by the weight of the same volume of water. It is, 
 therefore, a measure of density, and gives the relative weight of the unit 
 volume of the material as compared to the weight of unit volume of water. 
 The higher specific gravity of the dolomitic hydrate is due to the fact 
 that only the lime present in the calcined dolomite combines with water, 
 the magnesia being present as the oxide. From the specific gravity and 
 the weight per cubic foot of any material it is possible to calculate the 
 amount of voids or the space occupied by the air. Assume the specific 
 gravity of a hydrate to be 2.50 and the weight to be 40 Ibs. to the cubic 
 foot. The specific gravity means that a cubic foot of perfectly solid 
 hydrate weighs 2.50 times as much as a cubic foot of water. A cubic 
 foot of water weighs 62.4 Ibs., then a cubic foot of hydrate (perfectly 
 solid containing no voids) would weigh 62.4 X 2.50 = 156 Ibs. The 
 hydrate, however, weighed only 40 Ibs. per cubic foot, therefore the air 
 occupied a space equal to such a volume of hydrate as would weigh 
 (156-40 = 116) 116 Ibs. The per cent of voids would be 116/156 = 74.4%. 
 
 Line No.4 is the residue insoluble in dilute hydrochloric acid (muriatic 
 acid) and consists of sand, clay, or ashes present in the hydrated lime. In 
 every case (except in hydraulic hydrates) this is inert material and has 
 no value as a binding agent; it should, therefore, be looked upon as an 
 impurity and in case the amount is over 2% it would materially injure 
 the sand carrying capacity of the hydrate. 
 
 47 
 
Line No. 5 gives the amount of water present as free (or mechanically 
 contained) moisture and not combined with the lime. This should be 
 present only in small quantities. If too great an excess of water is 
 present the hydrate will have a tendency to lump or cake. 
 
 Line No. 6 gives the amount of water which has entered into chem- 
 ical combination with the lime to form the hydrate and which is a neces- 
 sary and important ingredient. The amount should always be sufficient 
 to satisfy all the calcium oxide present. Attention has been called to the 
 fact that the amount of combined water is always greater in the high 
 calcium hydrates. 
 
 Line No. 7 gives the carbon dioxide (carbonic acid gas) present in 
 the hydrate. This gas is in combination with the lime and denotes either 
 the presence of unburned limestone (core) or that the hydrate has taken 
 up carbonic acid from the atmosphere; in any case the amount present 
 should be small, less than 2%, otherwise it indicates an inferior hydrate. 
 The lime already combined with carbonic acid is inert and unable to 
 contribute any strength to the mortar. 
 
 Line No. 8 : in this horizontal line the amount of caustic oxides present 
 has been calculated, that is, the amount of bonding material which is capable 
 of uniting with the carbonic acid of the atmosphere thereby producing 
 the bond of the mortar. This is deduced by subtracting from 100 the 
 residue insoluble in hydrochloric acid (4), moisture (5), combined 
 water (6) and the amount of calcium carbonate corresponding to the 
 
 C(7)X100 ) 
 amount of carbonic acid present in the hydrate < - 
 
 The numbers in parenthesis refer to the horizontal lines in the 
 preceding table. 
 
 48 
 
USE OF HYDRATED LIME IN SAND 
 MORTARS 
 
 CHAPTER VIII 
 
 IT may be stated that hydrated lime is suitable for any use in the 
 building trade to which lump lime can be put. This in general 
 includes its use in mortars and plasters aH44lrWouId appearthttt-fts 
 thejnaterial^becQmes better known, its advantages will be found to 
 outweigh any disadvantages. 
 
 A i^tftar made with hydrated lime often does not trowel quite so 
 easily as a mortar made from lime putty. The smooth working qualities 
 of the hydrate can be greatly improved by proper method of manufac- 
 turing and by allowing the mortar or paste to soak over night so that the 
 gauging water becomes thoroughly incorporated. The great ease of 
 handling hydrate and the thoroughness with which it has been slaked 
 make up to a great extent for any lack of plasticity. 
 
 The use of hydrated lime does away with the necessity of slaking 
 lime to a paste, thus saving the cost of slaking. It is estimated that it 
 costs 25 cents a barrel to slake lime in a mortar box. Hydrated lime comes 
 into the market in convenient packages of a definite weight. This makes 
 it possible to proportion the mortar so as to have exact quantities of lime 
 and sand present, a fact which is always appreciated both by the archi- 
 tect and engineer. It is much more difficult to obtain accurate propor- 
 tions of lime and sand when lump lime is used, especially as it is a general 
 custom to add as much sand as possible with the result that the mortar 
 is often over-sanded and possesses little strength. 
 
 ADVANTAGES OF In June, 1910, the author presented the results 
 HYDRATED LIME obtained from an extended series of tests on mortars 
 made from both hydrated and lump lime, to the 
 American Society for Testing Materials.* One of the most important 
 conclusions drawn from these investigations was that the mortar produced 
 from hydrated lime was stronger than that produced from the correspond- 
 ing lump lime slaked to a paste. This conclusion was to be expected, 
 since it is possible to manufacture hydrated lime by mechanical means 
 under good chemical control, which is more thoroughly slaked than it is 
 possible to slake lump lime on the job. The user in dealing with hydrated 
 lime is handling a product which can be definitely proportioned and will 
 *Proceedings American Society for Testing Materials, 1910. 
 
 49 
 
produce known results. The quality of hydrate desired can be specified 
 in advance and the material can be inspected and tested (see specifica- 
 tion for hydrate, page 84) in order to determine if it fulfills the require- 
 ments. The quality of quicklime can also be specified and its character 
 determined by tests, but such tests do not indicate what will be the 
 quality of mortar found on the job, since lime is chemically changed 
 during slaking. Hydrated lime undergoes no further change upon the 
 addition of water, therefore the same material is tested which is to be 
 used. The testing of hydrated lime is no more difficult than the testing 
 of cement. With lump lime the user is dependent always upon the 
 thoroughness of slaking and it is well known that unless the paste is 
 run off and stored for some considerable time, there is no assurance of 
 complete and thorough slaking. 
 
 Practically all those who investigated the strength of lime mortars 
 have recommended the use of hydrated lime rather than lump lime. 
 In Circular No. 30, 1911 of theBureau of Standards, the following statement 
 is made: "The proportion of impurities in hydrated lime is generally 
 less than that in the lime from which it is made. In building operations 
 hydrated lime may be used for any purpose in place of lump lime, with 
 precisely similar results. The consumer must pay the freight on a large 
 amount of water, but the time and labor required for the slaking is 
 eliminated and there is no danger of spoiling it either by burning or in- 
 complete slaking * * *. For all building purposes hydrated lime 
 is to be preferred to lump lime. By its use the time and labor involved 
 in slaking may be saved and the experience of the laborer is eliminated 
 as a factor in the problem." From the above it will be seen that those 
 who have carefully investigated hydrated lime are firm in their opinion 
 that it is safer and superior to lump lime. 
 
 In the past when lump lime was used almost exclusively for plaster- 
 ing, it was the practice to slake the lime and allow it to season for some 
 considerable time before using in order that the plaster should contain 
 no particles of quicklime. This occasionally caused delay in the con- 
 struction of buildings. Moreover, plaster made from lime does not set 
 quite so rapidly or in the same manner as gypsum plaster. These two 
 points have led people to believe that buildings plastered with hydrated 
 lime are delayed in the course of construction. By the use of hydrated 
 lime the delay due to slaking and seasoning is done away with, and by a 
 proper method of planning and rotating the work, the job can be com- 
 pleted without delay. 
 
 50 
 
SECOND NATIONAL BANK BUILDING, TOLEDO, OHIO 
 
 D. H. BURNHAM Co., CHICAGO, ILL., ARCHITECTS 
 
 Hydrated Lime Plaster Used Throughout for Scratch, Brown and Finish Coats 
 
SELECTION In the preparation of mortar or plaster, generally little atten- 
 OF SAND tion is paid to the quality of the sand employed. Since the 
 sand forms three-quarters or more of the mortar, it follows 
 that the strength is largely dependent upon the quality of the sand used. 
 Sand for use in lime mortars should be clean, free from dirt and loam, 
 and as coarse as is consistent with the character of surface desired. 
 
 Investigations of sands have shown that coarse sand yields a stronger 
 mortar than fine sand. It is better to use as coarse sand as possible if a 
 strong mortar is desired. This is particularly the case in mortars used 
 in brick work where the joints between the bricks are wide. The grada- 
 tion of the sand grains, that is, the amount of the different sized grains 
 present, should be such as to give the greatest density or the least voids 
 in the sand. The following specifications for a mortar sand are taken 
 from Bulletin No. 70, University of Illinois: 
 
 "The sand shall consist of grains of hard, tough, durable rock and 
 must be free from soft, decayed or friable material. 
 
 "The suspended matter shall not exceed 6% by weight. 
 
 "Not more than 15% by weight, including the suspended matter, 
 shall pass a No. 100 screen nor more than 80% a No. 16 screen. 
 
 "The voids shall not exceed 35% of the total volume." 
 
 SAND-CARRYING The statement is often made that hydrated lime will 
 CAPACITY OF not carry so much sand as lime paste. This is really 
 HYDRATED LIME not the case. It is not to be expected that 200 pounds 
 of hydrated lime will carry as much sand as 200 pounds 
 of lump lime slaked to a paste for the simple reason that 200 pounds 
 of hydrate contains less calcium and magnesium oxides than the paste 
 resulting from slaking 200 pounds of lump lime. By referring to the 
 equation for slaking lime on page 15, it will be seen that 56 pounds of 
 pure high calcium lime gave 74 pounds of hydrate; therefore, 200 pounds 
 of lime would give (56:74 = 200 :X) 264 pounds of dry hydrate. Thus 
 264 pounds of hydrated lime contains the same amount of calcium and 
 magnesium oxide as 200 pounds of lump lime slaked to a paste. It 
 would require 264 pounds of hydrate to carry the same amount of sand 
 as 200 pounds of lump lime. 
 
 MACHINE MIXED Within the last few years machines have been placed 
 MORTAR on the market to mix the sand and lime, these machines 
 
 being similar in operation to a concrete mixer. By 
 the use of such machines, it is possible to mix the lime and sand more 
 thoroughly and the mixing is accomplished in less time than is required 
 by hand. Hydrated lime is especially adapted for use in the mortar 
 mixer because the material comes on the work in a convenient form and 
 in packages of known weight. 
 
 52 
 
On a recent job with which the author is familiar, all the mortar 
 used in the brick work was mixed in this manner. The mixing machine 
 was operated only during the last few hours in the afternoon, enough 
 mortar being prepared for next day's requirements. The mortar mixed 
 in the machine was dumped into the basement in a pile and was allowed 
 to age over night. When used the mortar was entirely satisfactory and 
 worked free and smooth. 
 
 PROPORTIONS OF Below are indicated the approximate proportions of 
 MATERIALS hydrate and sand to be employed in mortar for various 
 
 uses. It is not possible to give specifications covering 
 all conditions, since different hydrates will carry varying quantities of 
 sand and more particularly because the character of the sand materially 
 influences the quantity of hydrate required. 
 
 PROPORTIONS FOR HYDRATED LIME PLASTER* 
 
 WOOD LATH THREE COAT WORK 
 
 The following are the proportions in which materials should be mixed 
 at the mixing plant or by the contractor on the job: 
 
 PER TON OF PER HUNDRED POUNDS OF 
 
 SANDED PLASTER HYDRATED LIME 
 
 SCRATCH COAT 
 
 1550 pounds sand 350 pounds sand 
 
 450 pounds hydrated lime 100 pounds hydrated lime 
 
 3J/2 pounds hair % pound hair 
 
 BROWN COAT 
 
 1600 pounds sand 400 pounds sand 
 
 400 pounds hydrated lime 100 pounds hydrated lime 
 
 13/2 pounds hair % pound hair 
 
 FINISH COAT, WHITE 
 Lime putty properly gauged with Plaster of Paris 
 
 SAND FLOAT FINISH 
 
 1450 pounds sand 275 pounds sand 
 
 550 pounds hydrated lime 100 pounds hydrated lime 
 
 *These are average mixtures for first class, clean, sharp plastering sand. 
 Mixtures may be changed to meet other qualities of sand. 
 
 53 
 
WOOD LATH TWO COAT WORK 
 
 PER TON OF PER HUNDRED POUNDS OF 
 
 SANDED PLASTER HYDRATED LIME 
 
 FIRST COAT 
 
 1550 pounds sand 350 pounds sand 
 
 450 pounds hydrated lime 100 pounds hydrated lime 
 
 3j^ pounds hair % pound hair 
 
 FINISH COAT, WHITE 
 Lime putty properly gauged with Plaster of Paris 
 
 SAND FLOAT FINISH 
 
 1450 pounds sand 275 pounds sand 
 
 550 pounds hydrated lime 100 pounds hydrated lime 
 
 METAL LATH THREE COAT WORK 
 
 PER TON OF PER HUNDRED POUNDS OF 
 
 SANDED PLASTER HYDRATED LIME 
 
 SCRATCH COAT 
 
 1550 pounds sand 350 pounds sand 
 
 450 pounds hydrated lime 100 pounds hydrated lime 
 
 4 pounds hair 1 pound hair 
 
 BROWN COAT 
 
 1600 pounds sand 400 pounds sand 
 
 400 pounds hydrated lime 100 pounds hydrated lime 
 
 l*/2 pounds hair Yi pound hair 
 
 FINISH COAT, WHITE 
 Lime putty properly gauged with Plaster of Paris 
 
 SAND FLOAT FINISH 
 
 1450 pounds sand 275 pounds sand 
 
 550 pounds hydrated lime 100 pounds hydrated lime 
 
 BRICK OR TILE THREE COAT WORK 
 
 PER TON OF PER HUNDRED POUNDS OF 
 
 SANDED PLASTER HYDRATED LIME 
 
 SCRATCH COAT 
 
 1600 pounds sand 400 pounds sand 
 
 400 pounds hydrated lime 100 pounds hydrated lime 
 
 \Yl pounds hair % pound hair 
 
 BROWN COAT 
 
 1600 pounds sand 400 pounds sand 
 
 400 pounds hydrated lime 100 pounds hydrated lime 
 
 FINISH COAT, WHITE 
 Lime putty properly gauged with Plaster of Paris 
 
 SAND FLOAT FINISH 
 
 1450 pounds sand 275 pounds sand 
 
 550 pounds hydrated lime 100 pounds hydrated lime 
 
 54 
 
BRICK or TILE TWO COAT WORK 
 
 PER TON OF PER HUNDRED POUNDS OF 
 
 SANDED PLASTER HYDRATED LIME 
 
 FIRST COAT 
 
 1600 pounds sand 400 pounds sand 
 
 400 pounds hydrated lime 100 pounds hydrated lime 
 
 1^2 pounds hair Y% pound hair 
 
 FINISH COAT, WHITE 
 Lime putty properly gauged with Plaster of Paris 
 
 SAND FLOAT FINISH 
 
 1450 pounds sand 275 pounds sand 
 
 550 pounds hydrated lime 100 pounds hydrated lime 
 
 ON CONCRETE 
 
 100 pounds sand 
 
 800 pounds hydrated lime 
 
 250 pounds calcined plaster 
 
 WOOD LATH, BRICK OR TILE ONE COAT W'ORK 
 
 1550 pounds sand 
 450 pounds hydrated lime 
 3J/2 pounds hair 
 
 GYPSUM BLOCK THREE COAT WORK 
 Use the same quantities as shown for Brick or Tile. 
 
 NOTE Mixtures specified on pages 53, 54 and 55 are average mixtures for first class, 
 clean, sharp plastering sand. Mixtures may be changed to meet other qualities of sand. 
 
 HAND MIXED In preparing these mortars, the best and most economical 
 MORTARS results will be obtained by the use of a mortar mixing 
 
 machine, several of which are on the market. If hand 
 mixing is to be used, two methods may be employed in preparing the 
 mortar. 
 
 FIRST Soak the hydrate with water so as to produce a thick paste, 
 and allow to stand over night, then add the desired amount of sand and 
 sufficient water to give the required consistency to the mortar. It is 
 generally conceded that this method produces the more plastic mortar. 
 
 SECOND Mix the hydrate and sand dry, the same as with cement 
 mortar, then add the water to produce the required consistency. 
 
 55 
 
When hair is used, it should always be well soaked and beaten before 
 mixing with the mortar. Thorough hoeing and mixing always improves 
 the plasticity and working qualities of a mortar. 
 
 LIME-CEMENT MORTARS 
 
 In many cases where a mortar having a greater strength is required, 
 or it is advisable to have considerable strength produced quickly, it is 
 advantageous to use Portland cement in the mixture. 
 
 Investigations by various authorities have proven the fact that 
 hydrated lime and Portland cement can be mixed in any proportions 
 from an addition of 10% of hydrate to the Portland cement for making 
 a cement mortar to an addittion of 10% of Portland cement to the 
 hydrate for making a hydrated lime mortar. The addition of hydrated 
 lime to a cement mortar improves the plasticity and water tightness, 
 and the addition of Portland cement to a hydrated lime mortar increases 
 the early time strength. 
 
 STRENGTH OF From the results obtained by many investigations it 
 CEMENT-LIME may be stated that the replacement of 25% of Portland 
 MORTARS cement with hydrate in mortar does not materially 
 
 weaken the mortar. Mr. Emley* from his investiga- 
 tion drew the following conclusion : 
 
 "1. While the strength does decrease with increasing proportions 
 of lime, samples containing 25% lime are not very much weaker than 
 those made of cement. 2. High calcium lime sets more rapidly than 
 dolomitic lime. Specimens containing the former are therefore stronger 
 when 7 days old. Those containing dolomite were almost as strong at 
 28 days and at 3 months had just about caught up to the high calcium 
 limes. 3. Samples stored under water set more slowly than those stored 
 in air, and were therefore weaker at 7 days. But at 3 months those 
 stored under water were much the stronger, frequently showing twice 
 the strength of the specimens stored in air. This applies equally to all 
 specimens containing 25% or less of lime, whether dolomitic or high 
 calcium." 
 
 Following will be found the results obtained from an extended 
 series of tests made under the direction of Prof. Ira H. Woolson of 
 Columbia University, N. Y.** 
 
 The charts on pages 57 to 60 clearly illustrate the greater strength 
 developed by mortars made with hydrated lime over those made from 
 the corresponding quick lime slaked to a paste. The curves plotted 
 were obtained by averaging the results on similar tests of three different 
 hydrated limes and three different quick limes. 
 
 *The use of hydrated lime in a Portland cement mortar, by Warren E. Emley and H. 
 P. Greenwald, Proceedings, National Lime Manufacturers Association, 1913. 
 
 """Comparative Test of Lime Mortar, both in tension and compression, by E. W. Lazell, 
 Proceedings of American Society for Testing Materials, Page 328, 1910. 
 
 56 
 
Tension Tests Average, 1 to 3 Mixture. 
 
 r .85 Cement, ^i f .50 Cement 
 t ,15 Lime, J 1 .50 Lime, 
 3 Sand. 3 Sand. 
 
 1 Lime, 
 3 Sand. 
 
 Quick- Hy- Quick- Hy- Quick- Hy- 
 
 lime. drate. lime. drate. lime. drate. 
 
 28 days 288 365 103 176 37 83 
 
 3 months.... 352 399.5 127 225 43 99 
 
 12 months 502 517 174 267 81 125 
 
 Percentage of Hydrated Lime is by weight of Portland cement 
 
 57 
 
Compression Tests Average, 1 to 3 Mixture. 
 
 ( .85 Cement, ) 
 1 .15 Lime, j 
 
 J .50 Cement, \ 
 t .50 Lime, j 
 
 1 Lime, 
 
 3 Sand. 
 
 3 Sand. 
 
 3 Sand. 
 
 - 
 
 
 Quick- 
 
 Hy- 
 
 Quick- 
 
 Hy- 
 
 Quick- 
 
 Hy- 
 
 
 
 lime. 
 
 drate. 
 
 lime. 
 
 drate. 
 
 lime. 
 
 drate. 
 
 28 
 
 davs . 
 
 1,999 
 
 2,170 
 
 704 
 
 858 
 
 230 
 
 210 
 
 a 
 
 "* j 
 months . . 
 
 . . 2,451 
 
 2,810 
 
 859 
 
 1,132 
 
 199 
 
 677 
 
 12 
 
 months. . 
 
 . . 4,001 
 
 4,263 
 
 1,837 
 
 2,116 
 
 273 
 
 840 
 
 Percentage of Hydrated Lime is by weight of Portland cement 
 
 58 
 
Tension Tests Average, 1 to 5 Mixture. 
 
 65 Cement. .35 Lime. 1 Lime, 5 Sand. 
 
 5 Sand. 
 
 Quicklime. Hydrate. Quicklime. Hydrate. 
 
 28 days . 99 214 33 36 
 
 3 months ... 112 316 48 60 
 
 12 months . 160 277 67 93 
 
 Percentage of Hydrated Lime is by weight^of^Portland cement 
 
 59 
 
COMPRESSION 
 
 SQO 
 
 7SC 
 
 ZB-D 
 
 J-M< 
 
 28 days 
 
 3 months. . 
 12 months. . 
 
 Compression Tests Average, 1 to 5 Mixtures. 
 
 .65 Cement, .35 Lime. 1 Lime, 5 Sand. 
 
 5 Sand. 
 
 Quicklime. Hydrate. Quicklime. Hydrate. 
 . " 574 1,339 126 175 
 
 642 1,801' 150 316 
 
 1,422 3,338 343 565 
 
 Percentage of Hydrated Lime is by weight of Portland cement 
 
 60 
 
EQUITABLE BUILDING, NEW YORK CITY 
 
 R. E. GRAHAM, CHICAGO, ARCHITECT 
 
 Hydrated Lime Used Throughout in All Brick Mortar 
 
It is often stated that lime made from dolomite is unsuitable for 
 use in connection with Portland cement because of the high magnesia 
 content. This is not the fact as is shown by the results given in the charts, 
 since these cover tests made on both high calcium and dolomitic limes. 
 It may be stated that the magnesia contained in dolomitic limes shows no 
 deleterious action but on the contrary is a valuable ingredient and con- 
 tributes to the strength of the mortars. 
 
 Proportions for hydrated lime-cement mortar, proportions being 
 given by weight: 
 
 BRICK MORTAR 
 
 THREE TO ONE MIXTURE Four bags Portland cement, one bag 
 (100 Ibs.) hydrated lime* and 1,500 pounds sand. 
 
 FOUR TO ONE MIXTURE Three bags Portland cement, one bag 
 (100 Ibs.) hydrated lime* and 1,600 pounds sand. 
 
 FIVE TO ONE MIXTURE Two bags Portland cement, one bag 
 (100 Ibs.) hydrated lime* and 1,500 pounds sand. 
 
 STAINLESS CEMENT MORTAR 300 pounds white cement, 100 pounds 
 hydrated lime and 1,200 pounds sand. 
 
 FOR TILE SETTING OR ROOFING TILE 85% of Portland cement, 
 15% of hydrated lime used with 3 parts sand. 
 
 CEMENT-HYDRATED LIME MORTAR FOR INTERIOR PLASTERING ON- 
 BRICK OR TERRA COTTA: 
 
 SCRATCH COAT (OR FIRST COAT) One bag Portland cement, 2 
 bags (200 Ibs.) hydrated lime and 1,200 pounds sand. 
 
 BROWN COAT (OR SECOND COAT) One bag Portland cement, 2 
 bags (200 Ibs.) hydrated lime and 1,200 pounds sand. 
 
 CEMENT MORTARS FOR FIREPROOFING PARTITIONS 100 pounds 
 hydrated lime to 400 pounds Portland cement, and 1,500 pounds sand. 
 
 *Hydrated lime is usually sold in 100 ll>. burlap or cotton sacks and 40 or 50 Ib. paper 
 sacks. 
 
USE OF HYDRATED LIME IN CONCRETE 
 
 CHAPTER IX 
 
 PLASTICITY OF During the time of mixing and placing concrete and 
 HYDRATED LIME up to the time of beginning of the hardening, concrete 
 may be considered as a plastic material. The term 
 plastic as used in reference to concrete and mortar may be denned as that 
 property which allows the material to be cast or moulded into shape. The 
 plastics differ from most materials of construction in that their strength 
 and structural integrity depend to a much greater extent on the skill of 
 the user than upon that of the manufacturer. For example, the quality 
 of concrete is much more dependent on the quality of stone, sand and 
 workmanship than on the quality of Portland cement. In a treatise of 
 this kind it is impossible to discuss in detail how the hardening of the 
 cement is affected by the character of the sand and stone and the method 
 of mixing and placing. It will be readily recognized that the quality of 
 the concrete is largely dependent upon its plasticity or the ease with 
 which the plastic mass of stone, sand, water and cement will flow into 
 place and assume its final form. This being the case, anything which 
 will improve the plastic quality of the wet mass without materially 
 decreasing its strength after hardening will be found advantageous. 
 
 VALUE IN MORTARS The value of concrete and mortars in construction 
 
 AND CONCRETE work depends upon the ease of manipulating them 
 
 in a plastic state supplemented by the quality of 
 
 subsequent hardening to a stone-like mass. It is possible to increase the 
 plasticity by using an excess of water, and this is commonly done. Two 
 defects are introduced by the use of too much water. 1st. There is 
 great danger of a separation between the stone and mortar (sand and 
 cement) if the mixture is too wet, resulting in weak stratified concrete. 
 2nd. The excess water over and above that required by the cement 
 must be expelled in part by gravity and in part by evaporation. Since 
 the original water occupies space, it follows that its removal results in 
 voids and a non-dense concrete. In large slabs the loss of the water may 
 cause shrinkage and cracks. The addition of a large amount of excess 
 water, w r hile it makes the cement mass easier to pour, always results in 
 a lack of density, thereby producing a weak concrete. 
 
 63 
 

 "1 "ll SB a s 
 89 sill IS II 
 as a 
 
 L 
 
 LEADER-NEWS BUILDING, CLEVELAND, OHIO 
 
 CHAS. A. PLATT, ARCHITECT 
 Hydrated Lime Used in All Concrete and Brick Mortar 
 
INCREASED It is well known that the addition of a small amount of 
 
 PLASTICITY hydrated lime (10% or more by weight, of the Portland 
 OF CONCRETE cement used) renders the concrete mass much more plastic 
 and that less water is required to make the mass work- 
 able. As the results of experiments and practical observation, it has been 
 proven that the small amount of hydrate improves greatly the ease of 
 handling the concrete and that it further results in a denser concrete. 
 The greatest advantage of the use of hydrate is this quality of rendering 
 the concrete mass more plastic. Because of this increased plasticity the 
 same amount of tamping results in a denser concrete. 
 
 An illustration of the increase in plasticity of concrete, due to the 
 addition of hydrated lime, recently came to the author's observation. 
 In the construction of a large dam in the Northwest, the quarry and rock- 
 crushing plant were located on a hillside, about 400 feet above the river. 
 Since no good sand was available, the fine part of the aggregate was 
 manufactured from the rock. The concrete mixing plant was also located 
 on the hill, above the crest of the dam, and practically all the concrete 
 was spouted into place through chutes about 285 feet long, which had 
 an inclination of 18. In this manner about 30,000 cu. yds. of concrete 
 was placed. The concrete used was a 1:3:5 mix, using cement, sand and 
 stone, with an addition of 10% hydrated lime. Without the addition 
 of the hydrate, the wet concrete would not flow in chutes, but would 
 dam up and then spill over the side. With the addition of hydrate, the 
 material flowed smoothly and there was very little separation of the 
 mortar from the stone. Throughout the construction of the whole dam, 
 test cylinders were made, 6" in diameter X 12" long, and these were 
 broken at regular intervals. These cylinders were made at the site of 
 the dam from the material being deposited. The result showed a con- 
 siderable improvement both in the quality and the strength of the con- 
 crete, due to the hydrated lime. 
 
 RETENTION OF SUFFICIENT It is a well known fact that lime paste tends 
 MOISTURE TO PREVENT to retain the water mechanically mixed 
 
 SHRINKAGE CRACKS IN with it. This quality of hydrated lime is 
 
 CONCRETE - particularly valuable when the concrete is 
 
 spread out in a thin sheet with one surface 
 
 exposed to the air, as is the case in concrete floors, sidewalks and roads. 
 Practical experience has shown that the more rapidly the mass dries, the 
 greater the likelihood of cracking. This cracking has been attributed to 
 the fact that the rate of surface evaporation is greater than the flow of 
 water from the interior to the surface, causing unequal drying, a condi- 
 tion which gives rise to strain and more or less marked ruptures. During 
 
 66 
 
CONCRETE ROAD, GARRET Co., MARYLAND 
 
 10% Addition of Hydrated Lime to 1-2-4 Concrete 
 
 (Monolithic Type) 
 
 the early period of drying out and until the concrete has set and hardened, 
 it has little or no strength, and its cohesion is negligible. In this condi- 
 tion it is evident that the slightest shrinkage must result in the formation 
 of cracks. Even though the cracks be so small as to be scarcely notice- 
 able, they are a source of weakness when the hardened concrete is subject 
 to tensile strains. The prevention of the formation of shrinkage cracks 
 is not so important in mass concrete subject only to compression or in 
 reinforced concrete where the tension is provided for by the steel rein- 
 forcement, but when used in a thin slab as is the case in concrete roads 
 and pavements, it is very important to reduce the cracks due to shrinkage 
 to a minimum. The addition of a small amount of hydrate to the concrete 
 mass reduces the formation of shrinkage cracks by rendering the mass 
 denser and thereby retarding the evaporation. Further, by rendering the 
 mass more plastic, it prevents the separation of the mortar from the stone, 
 thus producing a more uniform mass. In some recent road work in 
 which 10% of hydrated lime was used throughout the concrete, it was 
 found that fewer cracks developed in this road than in sections having 
 the same composition but in which no hydrate was used. 
 
1 1 ** 
 
 
 BHB 
 
METHODS OF Concrete can be rendered water-tight in a number 
 WATERPROOFING of ways: 
 
 CONCRETE 1. By carefully grading and proportioning the aggre- 
 
 gate and the cement. 
 
 2. By the application of layers of materials impervious to water, 
 such as asphalts, bitumen, etc., with or without cloth or felt. 
 
 3. By plastering the outside surface of the concrete with a rich 
 Portland cement mortar. 
 
 4. By the introduction of some foreign material or materials into 
 the mixture. 
 
 Ignoring the methods mentioned under Nos. 2 and 3, which both 
 depend for their water-proofing quality upon a layer of material impervi- 
 ous to water, thus keeping the water away from the concrete itself, but 
 which do not render the concrete mass impervious to water, we will 
 deal only with Nos. 1 and 4. The greatest objection to the use of imper- 
 vious materials such as asphalt, bitumen, etc., either with or without 
 felt or cloth, is the durability of the materials themselves. In a few years, 
 most, if not all, of these substances oxidize, disintegrate and become 
 porous. 
 
 Method No. 1 depends on selecting materials which are so graded 
 that they give the densest possible concrete. This method is fully 
 described in Taylor and Thompson's book on "Concrete, Plain and 
 Reinforced." The method requires a careful selection of the sand and 
 stone, careful proportioning of the same, and extreme care in mixing 
 and placing. 
 
 NECESSARY QUALIFICATIONS It would be a great advantage to engineers 
 FOR WATERPROOFING if some method of rendering concrete more 
 
 MATERIAL - impervious to water were known. Thus, if 
 
 some ingredient could be added to the con- 
 crete mass to produce this, the advantage would be apparent. Such an 
 ingredient should possess the following characteristics: 
 
 1. It should be easily mixed with the materials forming the con- 
 crete aggregate. 
 
 2. It should not in any way injure the character of the concrete 
 or have a deleterious action on the cement. 
 
 3. It should be preferably of a character chemically similar to that 
 of the cement. 
 
 4. It should not be subject to alteration, decomposition or 
 decay, and should be a mineral compound rather than organic. 
 
 70 
 
5. The material should be bulky and preferably of a colloidial 
 nature, so as to fill the interstices of the concrete mass. 
 
 6. It should not be so expensive as to make the cost of the con- 
 crete excessive. 
 
 7. It should be easily procurable and handled. 
 
 In looking over these requirements, it will be seen that such materials 
 as oils, waxes and other organic bodies do not fulfill the specifications. 
 They are not of a character similar to the cement, are not easily mixed 
 with the concrete aggregate, and, as they are organic, are subject to 
 alteration and decay. Most of the so-called water-proof compounds on 
 the market at the present time which are to be incorporated in the con- 
 crete mass itself contain organic bodies, such as the lime salts of fatty 
 acids, oils, paraffin or Japanese wax, either alone or in combination with 
 other ingredients. While the action of these bodies is to render the con- 
 crete mass in the early stages less impervious to water, it is doubtful 
 how long this beneficial action will continue. 
 
 In a report of the committee on water-proofing rendered to the 
 American Society for Testing Materials and published in the Proceed- 
 ings for 1907, the following statement is made: 
 
 "The only conclusion possible at the time, from data so far obtained, 
 indicates that the majority of waterproofing compounds examined under 
 the j urisdiction of sub-committee A, are no more effective than untreated 
 properly proportioned mixtures which certainly can be made absolutely 
 w^ater-proof by the use of proper materials and well proportioned mix- 
 tures." 
 
 Experiments made under the author's direction confirm these con- 
 clusions as applying to water-proof compounds which contain organic 
 materials. 
 
 HYDRATED LIME AS Referring again to the specifications, it will be seen 
 
 A WATERPROOFING that a material to meet the requirements fully 
 
 MATERIAL should have a mineral base and should be composed 
 
 chiefly of lime so as to be similar to cement in its 
 
 chemical characteristics. It would, therefore, seem that hydrated lime 
 would be a material which would most nearly fill the requirements. Clay 
 has been suggested as a suitable material, but its use in practice would be 
 impracticable owing to the tendency of its particles to adhere, forming 
 balls; these balls have little adhesion, and hence injure the strength 
 of concrete. 
 
 71 
 
RESERVOIR AT WALTHAM, MASSACHUSETTS 
 FlVE PER CENT. OF HYDRATED LlME ADDED BY WEIGHT OP CEMENT 
 
 The following results of tests are given to illustrate the water- 
 proofing properties of hydrated lime: 
 
 TENSILE STRENGTH LBS. PER SQUARE INCH* 
 1-3 Tests Water Exposure 
 
 Age of 
 Test Piece 
 
 .95 P. C. 
 .05 L. 
 3 Sand 
 
 .90 P. C. 
 .10 L. 
 
 3 Sand 
 
 .85 P. C. 
 .15 L. 
 
 3 Sand 
 
 .80 P. C. 
 .20 L. 
 3 Sand 
 
 .75 P. C. 
 .25 L. 
 
 3 Sand 
 
 .70 P. C. 
 .30 L. 
 
 3 Sand 
 
 7 days 
 28 days 
 3 months 
 6 months 
 9 months 
 12 months 
 
 157 
 311 
 389 
 321 
 301 
 336 
 
 189 
 364 
 419 
 341 
 308 
 311 
 
 239 
 264 
 372 
 278 
 279 
 322 
 
 237 
 
 268 
 374 
 260 
 268 
 299 
 
 173 
 259 
 314 
 207 
 250 
 260 
 
 173 
 
 268 
 281 
 253 
 232 
 231 
 
 NOTE P. C., Portland Cement; L., Hydrated Lime. 
 
 Percentage of Hydrated Lime is by weight of Portland cement 
 
 These results indicate that quite large additions of hydrated lime 
 can be made to cement mortars even when they are exposed to the action 
 of water. The hydrated lime in this instance acts as a filling material, 
 and as it is of a colloidial nature should render the mortar more imper- 
 vious to water. 
 
 In order to investigate this water-tight character of mortar, circular 
 pats were made of the different mixtures 3" in diameter and 1" thick. 
 *Lazell Proceedings American Society for Testing Materials, 1908. 
 
 72 
 
These were then placed in an apparatus in such a manner that the water 
 could act upon them in the centre through an opening exactly 2" in 
 diameter. Thus the area acted upon is 3.1416 square inches. 
 
 All pats were subjected to a pressure of thirty pounds for one hour. 
 
 PERMEABILITY TESTS 1-3 MIXTURES* 
 
 Composition of 
 Test Piece 
 
 Amount of water 
 
 passing through test piece in one hour under 30 Ib. 
 head, in cubic centimeters 
 
 Age of Test Piece 
 
 7 days 
 
 28 days 
 
 Remarks 
 
 IP. C. 
 
 3 Sand 
 
 10 cc 
 
 
 
 
 .95 P. C. 
 .05 Hydrate 
 3 Sand 
 
 5cc 
 
 
 
 Equivalent to replacing 
 5% of the cement by 
 Hydrate 
 
 .90 P. C. 
 .10 Hydrate 
 3 Sand 
 
 2cc 
 
 
 
 Equivalent to replacing 
 10% of the cement by 
 Hydrate 
 
 .85 P. C. 
 . 15 Hydrate 
 3 Sand 
 
 0.3cc 
 
 
 
 Equivalent to replacing 
 15% of the cement by 
 Hydrate 
 
 NOTE P. c Portland Cement. 
 
 Percentage of lime is in terms of weight of cement. 
 
 PERMEABILITY TESTS. 1-5 MIXTURES 
 
 28 days 6 Weeks Remarks 
 
 IP. C. 
 
 5 Sand 
 
 3000 cc 1090 cc 
 
 .95 P. C. 
 
 .05 Hydrate 
 5 Sand 
 
 Equivalent to replacing 
 5 cc 3 cc 5% of the cement by 
 Hydrate 
 
 .90 P. C. 
 
 . 10 Hydrate 
 5 Sand 
 
 Equivalent to replacing 
 2 . 5 cc 10% of the cement by 
 Hydrate 
 
 .85 P. C. 
 . 15 Hydrate 
 5 Sand 
 
 Equivalent to replacing 
 15% of the cement by 
 Hydrate 
 
 NOTE P. C., Portland Cement. 
 Percentage of lime is in terms of weight of cement. 
 
 *E. W. Lazell Proceedings American Society for Testing Materials, 1908. 
 
 73 
 
Referring to the preceding tests it will be seen that the addition of 
 even small amounts of hydrated lime to mortar materially increases its 
 water-tightness. 
 
 Sanford E. Thompson,* in an address delivered before the 
 American Society for Testing Materials, in June, 1908, gave tests upon 
 the concrete used for the Waltham, Mass., reservoir as follows: 
 
 "A few permeability tests with hydrated lime admixtures made by 
 the writer in 1903 indicated it to be a valuable material for water-proof- 
 ing. Later in 1906 when the reservoir at Waltham, Mass.,** which is 
 100 feet in diameter and 43 feet high, was under consideration, the writer 
 was consulted by Bertram Brewer, City Engineer, in the framing of 
 the specifications and made another series of tests as follows: 
 
 Permeability Test of 1:2:4 Concrete for Waltham, Mass., Reservoir, 1906 
 Concrete 4 in. thick. Pressure 80 Ibs. per sq. in. 
 
 Percentage of 
 Hydrated Lime 
 
 Flow in Grams per minute 
 
 At 14 days 
 
 At 21 days 
 
 At 28 days 
 
 0% 
 
 A 
 
 5.52 
 9.20 
 
 2.82 
 
 2.92 
 2.55 
 1.49 
 
 1.91 
 1.63 
 0.76 
 
 Percentage of lime is in terms of weight of cement. 
 
 "This flow is much greater than in the tests described at Cambridge, 
 but the pressure in the Cambridge tests is about one- third higher, the 
 age is greater, and probably, most important of all, the thickness of 
 concrete is twice as great. 
 
 "As a result of those tests for Waltham, 5% of hydrated lime was 
 adopted for the reservoir to mix with the 1 :2 :4 concrete in building its 
 walls. The results were satisfactory, the only seepage occurring at 
 joints formed between different day's work, where the bond between 
 the old and the new concrete was not made with sufficient care.'* 
 
 fin a recent address by Sanford E. Thompson, given before the 
 American Society for Testing Materials, in June, 1908, he discussed a 
 series of tests made on concrete composed of Portland cement, sand and 
 stone in varying proportions to which had been added varying amounts 
 of hydrated lime. In making these tests, concrete cubes were used con- 
 taining an embedded pipe through which the water pressure could be 
 applied. The results are given in the table on following page: 
 *Engineering Record June 27, 1908. 
 
 **Engineering Record January 12, 1907, Page 32. 
 tEngineering Record June 27, 1908. 
 
 74 
 
Flow of water 
 under 7-ft. head 
 
 Flow under pressure 
 of 60 Ibs. per sq. in. 
 
 
 
 
 
 
 
 Pressure 
 
 
 
 
 Per cent. 
 
 
 Duration 
 
 Flow 
 
 
 applied 
 
 Duration 
 
 Flow 
 
 Mark 
 
 Hydrat- 
 ed Lime 
 
 Age 
 
 of meas- 
 ured flow 
 
 Grams 
 Hour 
 
 Age 
 
 before 
 measure 
 
 of meas- 
 ured flow 
 
 Grams 
 per 
 Hour 
 
 Days 
 
 Hours 
 
 Days 
 
 Hours 
 
 Hours 
 
 1:2:4 concrete 
 
 
 
 
 
 
 
 
 
 No.l 
 
 1% 
 
 18 
 
 161 
 
 2.7 
 
 40 
 
 24 
 
 4M 
 
 74.8 
 
 No. 2 
 
 4% 
 
 18 
 
 161 
 
 1.2 
 
 41 
 
 18 
 
 5 
 
 28.4 
 
 No. 3 
 
 7% 
 
 18 
 
 161 
 
 1.0 
 
 42 
 
 18 
 
 G% 
 
 5.2 
 
 No. 4 
 
 10% 
 
 15 
 
 161 
 
 1.0 
 
 46 
 
 6 
 
 18 
 
 1.6 
 
 1:2^:4^ con. 
 
 
 
 
 
 
 
 
 
 No. 5 
 
 0% 
 
 30 
 
 169 
 
 0.3 
 
 44 
 
 17 
 
 6 
 
 1.1 
 
 No. 6 
 
 o% 
 
 30 
 
 169 
 
 1.9 
 
 45 
 
 18 
 
 6 
 
 32.5 
 
 No. 7 
 
 10% 
 
 29 
 
 169 
 
 0.8 
 
 49 
 
 
 11 
 
 
 
 No. 8 
 
 14% 
 
 29 
 
 169 
 
 0.7 
 
 50 
 
 
 27 
 
 
 
 1:3:5 concrete 
 
 
 
 
 
 
 
 
 
 No. 9 
 
 o% 
 
 26 
 
 169 
 
 9.8 
 
 50 
 
 6 
 
 14 
 
 70.6 
 
 No. 10 
 
 8% 
 
 26 
 
 169 
 
 1.1 
 
 51 
 
 8 
 
 17 
 
 3.6 
 
 No. 11 
 
 14% 
 
 28 
 
 169 
 
 1.1 
 
 50 
 
 28 
 
 13 
 
 10.7 
 
 No. 12 
 
 20% 
 
 28 
 
 169 
 
 1.2 
 
 53 
 
 9 
 
 15 
 
 0.7 
 
 "The percentages of hydrated lime are based on the weight of the 
 cement, these being added to the cement and not replacing it. The 
 variations in the ages of the specimens in different proportions slightly 
 affects the results and accounts in part for the fact that the 1 :3 :5 mix- 
 tures in the pressure tests are nearly as water-tight as the richer propor- 
 tions. Specimen No. 5, which shows practically no flow, is evidently 
 erratic." 
 
 He concludes from these experiments as follows: 
 
 " (1) Hydrated lime increases the water- tight ness of concrete. 
 
 "(2) Effective proportions of hydrated lime for water-tight con- 
 crete are as follows: 
 
 "For one part Portland cement: 2 parts sand: 4 parts stone, add 
 8 per cent hydrated lime. 
 
 "For 1 part Portland cement: 2J/^ parts sand: 4 3^ parts stone, add 
 12 per cent hydrated lime. 
 
 "For 1 part Portland cement: 3 parts sand: 5 parts stone, add 16 
 per cent hydrated lime. 
 
 "These percentages are based on the weight of the dry hydrated 
 lime to the weight of the dry Portland cement. 
 
 " (3) The cost of large waterproof concrete structures frequently 
 may be reduced by employing leaner proportions of concrete with hy- 
 drated lime admixtures, and small structures, such as tanks, may be 
 made more water-tight. 
 
 " (4) Lime paste made from a given weight of hydrated lime oc- 
 cupies about 2 J4 times the bulk of paste made from the same weight of 
 Portland cement, and is therefore very efficient in void filling. 
 
 75 
 
5 "i 
 
 < e- 
 
 \ I 
 
 I I 
 
 1 
 
 a 3 
 
 H 
 
 03 tJ 
 
 g 5 
 
 2 
 
 S ^3 
 
 ^ E& 
 
"Although the character of the sand and stone used in the concrete 
 will affect the best percentage of lime to use, the present materials are 
 representative of average materials throughout the country so that the 
 results should be of general application. Coarser sand would naturally 
 require slightly larger percentages of lime and finer sand, that is, sands 
 having a larger percentage of fine grains, which pass a sieve with 40 
 meshes to the linear inch, would be apt to require less lime since sands 
 containing considerable fine material produce a more water-tight al- 
 though a weaker concrete." 
 
 In these experiments of Thompson a water pressure of 60 pounds to 
 the square inch was used, which is equivalent to a head of about 140 
 feet. This is more severe than is encountered in the general engineering 
 practice. 
 
 The conclusions to be drawn from the investigations given indicate 
 that in hydrated lime we have the best material at present known for 
 rendering concrete water-tight. Hydrated lime,] however, must not be 
 confounded with quick-lime, which is absolutely unfit to be used in 
 concrete. The effect of the addition of hydrated lime in small quantities 
 is mostly mechanical, filling the voids, thus making the concrete imper- 
 vious to water. The quantity which should be used depends upon the 
 fineness of the sand employed and the proportions of the mixture. The 
 concrete materials must be properly graded, the proper proportions of 
 cement and hydrated lime used. Even with this preliminary care, if 
 the concrete is poorly mixed with insufficient water, or improperly 
 placed, or if joints are left, the walls will inevitably leak. The mixing 
 must be thorough; sufficient water must be employed to give a " mushy '* 
 mixture so that it will settle into place with the least amount of ramming. 
 Fully as important as the care in mixing is the bonding of one day's 
 concrete with the next; even small interruptions of an hour on a hot day 
 will materially injure the bond of the concrete. It is, therefore, necessary 
 that if water-tight work is to be done, the greatest care should be exer- 
 cised both in the selection of the materials, proportions of the ingredients, 
 mixing and placing the same. Hydrated lime can be advantageously used 
 only in mixtures as lean or leaner than 1-2-4 unless the hydrated lime 
 is substituted for an equal weight of cement. Ten per cent by weight 
 of the cement has been found a convenient amount in a number of 
 instances. Hydrated lime is a bulky material, the same weight oc- 
 cupying about two and one-half times the volume of the same weight 
 of cement. 
 
 77 
 
HOTEL OREGON, PORTLAND, OREGON 
 
 DOTLE-l'ATTERSON, ARCHITECTS 
 Hydrated Lime Used in Concrete and Brick Mortar 
 
ADVANTAGES OF HYDRATED LIME 
 OVER OTHER FORMS OF LIME. 
 
 CHAPTER X 
 
 HYDRATED lime is generally purer than the quick lime from which 
 I it is made. Chapter VIII, Page 50. 
 
 Hydrated lime is easily subjected to inspection and tests, and the 
 same material is tested as is used. Chapter VIII, Page 50. 
 
 The use of hydrated lime does away with the slaking of lump 
 lime, hence saves the cost and the space required for this operation. 
 Chapter VIII, Page 50. 
 
 Hydrated lime is thoroughly slaked and this fact can be deter- 
 mined by tests. Chapter VIII, Page 50. 
 
 By the use of hydrated lime mortar definite proportions can be 
 maintained. This is a difficult matter with lump lime. Chapter VIII, 
 Page 49. Table Page 53. 
 
 The putty or mortar made w T ith hydrated lime requires no aging 
 to be assured of thorough slaking. The Romans recognized the neces- 
 sity of long aging for lime paste and an old Roman law required that 
 lime be slaked three years before using. In the south of Europe at the 
 present time it is the custom to slake lime the season before it is used. 
 Chapter V, Page 38. 
 
 Hydrated lime can be economically mixed by means of a mortar 
 mixer. Chapter VIII, Page 52. 
 
 Mortars made from hydrated lime are stronger than mortars made 
 from lump lime slaked to a paste. Chapter VIII, Pages 57 to 60. 
 
 Hydrated lime can be mixed with cement mortar or concrete in any 
 desired proportions. It is a very difficult matter to mix lime paste 
 with cement thoroughly. Chapter VIII, Page 56. 
 
 Hydrated lime can be stored without danger of fire. No heat is 
 generated when water comes in contact with hydrate. 
 
 Hydrated lime is not apt to be spoiled by air slaking, as is the 
 case with lump lime. Often large amounts of lime are lost in this manner. 
 
 Hydrated lime comes into the market in packages of definite weight 
 and convenient size. 
 
 79 
 
The paper sacks generally used cost less than half as much as the 
 barrels required to hold an equal weight of lump lime. 
 
 The paste made from hydrated lime requires no screening. 
 
 There is no loss in the form of "core" when hydrated lime is used. 
 
 Against all these advantages only two objections are obvious. One, 
 the mortar made from hydrated lime often works harder and is less 
 plastic than that made from lump lime. This difficulty is generally 
 greatly exaggerated. Second, hydrated lime will not carry so much sand 
 as a corresponding weight of lump lime. This fact has been explained 
 on page 52. 
 
 The second objection is dependable upon the first, because the larger 
 sand carrying capacity of lump lime paste is due to its plasticity, or 
 buttery, easy working quality. This quality of lump lime usually results 
 in the addition of too much sand. The oversanding of lime mortar is 
 very generally practiced, since it is the custom to add as much sand as 
 possible in order to cheapen the cost of the mortar. This results in a 
 lean, oversanded mortar possessing little strength. The manufacturers 
 of lime are not blameless in this respect, since they have educated the 
 public to believe that the greater the yield of paste from a barrel of 
 lime the more sand it will carry, overlooking the fact that a leaner lime, 
 or one which does not yield as great a volume of paste, produces a much 
 stronger mortar. 
 
 The increase in bulk when lime is slaked is mostly due to the water 
 mechanically absorbed. When the lime mortar hardens, this water 
 evaporates, causing it to shrink and the excess water is therefore a source 
 of weakness and not strength. The greater the amount of water held 
 mechanically, the greater the volume of the paste, and therefore the less 
 the amount of binding ingredient or lime contained in a volume of paste. 
 This point is brought out clearly from the table on page 35. 
 
 It has been proven by many experiments that the poorer limes make 
 the stronger mortars. These poor, or lean limes contain clay, which 
 unites with the lime during the process of burning, and the presence of 
 this clay imparts some hydraulic or hardening properties to the mortar. 
 These hydraulic limes are largely used in Europe, but, unfortunately, 
 little of this material has been manufactured in this country. Practically 
 the same results can be obtained by the use of a mixture of hydrated 
 lime and Portland cement. 
 
 From all the advantages possessed by hydrated lime it would appear 
 to be the best form of lime to be used. It is perfectly logical that the 
 process of slaking should be taken away from the haphazard manner 
 used on the work and done at the point of manufacture of the lime where 
 skillful supervision is possible. 
 
 80 
 
APPENDIX I. 
 
 Useful Data Lime. 
 
 DEFINITION Lime is the product resulting from calcining (burning) of 
 
 limestone, which slakes upon the addition of water. 
 WEIGHT Lump lime weighs from 50 to 60 pounds per cubic foot. 
 BARREL A 200 pound barrel of lime contains 185 pounds net of 
 
 lump lime, or 3.1 cubic feet. 
 
 A 300 pound barrel of lime contains 280 pounds net of lime or 4.7 
 
 cubic feet. 
 BUSHEL A bushel of lime is from 75 to 80 pounds, depending upon 
 
 the law in the state in which the lime is purchased. 
 
 A bushel contains from 1 to 1.3 cubic feet. 
 PASTE Lime paste is a mixture of slaked lime and water. 
 SLAKING A pound of high calcium lime requires from 1 to 1J^ 
 
 pounds of water to form a paste. 
 
 A pound of dolomitic lime requires about 1 pound of water to form 
 
 a paste. 
 
 A barrel of high calcium lime requires from 30 to 40 gallons of water 
 
 to produce a paste. 
 
 A barrel of dolomitic lime requires from 25 to 30 gallons of water 
 
 to produce a paste. 
 
 SLAKING Slaking is the most important operation in preparing mortar. 
 BURNING Lime must not be burned in slaking. 
 
 Burning results from the use of too little water or insufficient mixing 
 
 during slaking. 
 DROWNING Lime must not be drowned in slaking. 
 
 Drowning results from the use of too much water. 
 AGING Lime used for plastering should be slaked at least 3 weeks 
 
 before using. The longer the paste is aged the better the quality 
 
 of the mortar. 
 VOLUME OF PASTE A barrel of lime gives from 6 to 9 cubic feet 
 
 of paste; average about 7^ cubic feet. 
 
 Hydrated Lime. 
 
 DEFINITION Hydrated lime is a dry, specially prepared slaked lime. 
 WEIGHT Hydrated lime weighs from 36 to 45 pounds per cubic 
 foot; average about 40 pounds. 
 
 81 
 
SACK A 100 pound sack of hydrated lime contains about 2J/2 cu- 
 bic feet. 
 
 PASTE It requires about an equal weight of water to produce a paste. 
 A 100 pound sack of hydrate gives about 2.3 cubic feet of paste of 
 ordinary consistency. 
 
 Portland Cement. 
 
 DEFINITION Portland cement is made from a mixture of materials 
 
 containing lime and clay. 
 
 WEIGHT A barrel of Portland cement weighs 376 pounds net, and 
 contains 3.8 cubic feet. 
 
 A bag of Portland cement weighs 94 pounds and contains about 
 
 1 cubic foot. 
 PACKED Packed cement weighs on the average 115 pounds to the 
 
 cubic foot. 
 LOOSE Loose Portland cement weighs on the average 92 pounds to 
 
 the cubic foot. 
 CUSTOMARY WEIGHT In general a sack of cement is considered to 
 
 be 1 cubic foot and to weigh 100 pounds. 
 PASTE Cement paste is a mixture of cement and water. 
 WEIGHT OF PASTE Cement paste weighs about 137 pounds to 
 
 the cubic foot. 
 
 Sand. 
 
 QUALITY The quality of sand is chiefly dependent upon the coarseness 
 
 and the relative size of the grains. 
 CLAY OB LOAM Clay or loam in sand is often injurious to mortar 
 
 because too much fine material is introduced. 
 SPECIFIC GRAVITY Specific gravity of sand is about 2.65. 
 WEIGHT Sand weighs from 80 to 120 pounds to the cubic foot, 
 
 average about 100 pounds. 
 COARSE SAND Coarse sand requires less water than fine sand and 
 
 gives a stronger mortar. 
 MIXED SAND Mixed sands usually weigh more and contain a smaller 
 
 volume of voids than coarse or small sands. 
 FINE SAND Fine sand with grains of uniform size weighs nearly the 
 
 same when dry and has nearly the same percentage of voids as 
 
 screened sand. Fine sand with ordinary moisture is lighter and 
 
 more porous than coarse sand. 
 VOIDS Voids are the spaces in a mass of sand or mortar that are 
 
 filled with water or air. 
 
 82 
 
VEGETABLE MATTER Even a small amount of vegetable matter 
 present in sand may result in a weak mortar. 
 
 Mortar. 
 
 DEFINITION Mortar is a mixture of sand and water with some binding 
 material, such as lime, cement, or both. 
 
 STRONGEST MORTAR Is obtained from those sands which produce the 
 smallest volume of plastic mortar. 
 
 FINE SANDS Always produce a mortar of less strength than coarse 
 sands. 
 
 MIXTURES OF FINE AND COARSE SANDS Often produce a stronger 
 mortar than either material alone. 
 
 CLAY OR LOAM In sand generally weakens a rich mortar and may 
 strengthen a lean mortar. 
 
 WEIGHT The weight of lime or cement mortar varies with the 
 proportions as well as with the materials of which it is composed. 
 Average weight of lime mortar is about 120 pounds per cubic foot. 
 Average weight of 1-3 cement mortar is 135 pounds per cubic foot. 
 
 PROPORTIONS Proportions must be accurately measured. 
 
 MIXING Mixing must be thorough. All mortars are improved by 
 long mixing. 
 
 MACHINE MIXING Machine mixing is better than hand mixing and 
 gives more plastic mortar. 
 
 Quantities. 
 
 AVERAGE WOODEN WHEELBARROW LOAD of broken stone is about 2.4 
 
 cubic feet. 
 
 AVERAGE WOODEN WHEELBARROW LOAD of sand is about 2J/2 cubic feet. 
 AVERAGE IRON WHEELBARROW LOAD of stone or gravel is about 3 cubic 
 
 feet. 
 AVERAGE IRON WHEELBARROW LOAD of sand is about 3j/ cubic feet. 
 
 SHOVEL A No. 2 shovel holds about 15 pounds of sand. 
 A No. 3 shovel holds about 18 pounds of sand. 
 A No. 4 shovel holds about 20 pounds of sand. 
 
 BUCKET A 3 gallon (12 quart) bucket holds 16 pounds of hydrata. 
 A 3 gallon (12 quart) bucket holds 35 pounds of sand. 
 A 3 gallon (12 quart) bucket holds 40 pounds of cement. 
 
 88 
 
APPENDIX II. 
 
 Standard Specifications for Hydrated Lime* 
 
 SERIAL DESIGNATION: C6-15. 
 
 The specifications for this material are issued under the fixed designa- 
 tion C6; the final number indicates the year of original issue, or in the 
 case of revision, the year of last revision. 
 
 ADOPTED, 1915. 
 
 1. DEFINITION. Hydrated lime is a dry flocculent powder resulting 
 
 from the hydration of quicklime, 
 
 2. CLASSES. Hydrated lime is commercially divided into four classes: 
 
 (a) High- Calcium ; 
 (b) Calcium; 
 (c) Magnesian ; 
 (d) High-Magnesian. 
 
 3. BASIS OF PURCHASE. The particular class of hydrated lime desired 
 
 shall be specified in advance by the purchaser. 
 
 I. CHEMICAL PROPERTIES AND TESTS. 
 
 4. SAMPLING. The sample shall be a fair average of the shipment. 
 
 Three per cent of the packages shall be sampled. The sample 
 shall be taken from the surface to the center of the package. A 
 2-lb. sample to be sent to the laboratory shall immediately be 
 transferred to an air-tight container, in which the unused portion 
 shall be stored until the hydrated lime has been finally accepted 
 or rejected by the purchaser. 
 
 5. CHEMICAL PROPERTIES. (a) The classes and chemical properties 
 
 of hydrated lime shall be determined by standard methods of 
 chemical analysis. 
 
 (b) The non- volatile portion of hydrated lime shall conform to 
 the following requirements as to chemical composition: 
 'Authorized reprint from the copyrighted Year Book for 1915 of the American So- 
 ciety for Testing Materials, Philadelphia, Pa. , U. S. A. 
 
 84 
 
CHEMICAL COMPOSITION 
 
 Properties Considered. 
 
 High- 
 Calcium 
 
 Calcium 
 
 Magnesian 
 
 High- 
 Magnesian 
 
 Calcium Oxide per cent 
 
 90 (min.) 
 
 85-90 
 
 
 
 Magnesium Oxide per cent. . 
 
 
 
 10-25 
 
 25 (min ) 
 
 Silica plus Alumina plus Oxide of 
 
 
 
 
 
 Iron max per cent. . 
 
 5 
 
 5 
 
 5 
 
 5 
 
 Carbon Dioxide, max., per cent 
 
 5 
 
 5 
 
 5 
 
 5 
 
 \Vater 
 
 Sufficient to 
 
 Sufficient to 
 
 Sufficient to 
 
 Sufficient to 
 
 
 hydrate the 
 
 hydrate the 
 
 hydrate the 
 
 hydrate the 
 
 
 calcium- 
 
 calcium- 
 
 calcium- 
 
 calcium- 
 
 
 oxide 
 
 oxide 
 
 oxide 
 
 oxide 
 
 
 content 
 
 content 
 
 content 
 
 content 
 
 II. PHYSICAL PROPERTIES AND TESTS. 
 
 6. FINENESS. A 100-g. sample shall leave by weight a residue of not 
 
 over 5 per cent on a standard 100-mesh sieve and not over 0.5 
 per cent on a standard 30-mesh sieve. 
 
 7. CONSTANCY OF VOLUME. Hydrated lime shall be tested to deter- 
 
 mine its constancy of volume in the following manner: 
 
 Equal parts of hydrated lime under test and volume-constant 
 Portland cement shall be thoroughly mixed together and gauged 
 with water to a paste. Only sufficient water shall be used to make 
 the mixture workable. From this paste a pat about 3 in. in dia- 
 meter and J/-2 in. thick at the center, tapering to a thin edge shall be 
 made on a clean glass plate about 4 in. square. This pat shall be 
 allowed to harden 24 hours in moist air and shall be without pop- 
 ping, checking, cracking, warping or disintegration after 5 hours* 
 exposure to steam above boiling water in a loosely closed vessel. 
 
 III. PACKING AND MARKING. 
 
 8 . PACKING. Hydrated lime shall be packed either in cloth or in paper 
 
 bags and the weight shall be plainly marked on each package. 
 
 9. MARKING. The name of the manufacturer shall be legibly marked 
 
 or tagged on each package. 
 
 IV. INSPECTION AND REJECTION. 
 
 10. INSPECTION. (a) All hydrated lime shall be subject to inspection. 
 
 (b) The hydrated lime may be inspected either at the place 
 of manufacture or the point of delivery, as arranged at the time of 
 purchase. 
 
 85 
 
(c) The inspector representing the purchaser shall have free 
 entry at all times while work on the contract of the purchaser is 
 being performed, to all parts of the manufacturer's works which 
 concern the manufacture of the hydrated lime ordered. The manu- 
 facturer shall afford the inspector all reasonable facilities for inspec- 
 tion and sampling, which shall be so conducted as not to interfere 
 unnecessarily with the operation of the works. 
 
 (d) The purchaser may make the tests to govern the acceptance 
 or rejection of the hydrated lime in his own laboratory or elsewhere. 
 Such tests, however, shall be made at the expense of the purchaser. 
 
 11. REJECTION. Unless otherwise specified, any rejection based on 
 failure to pass tests prescribed in these specifications shall be re- 
 ported within five working days from the taking of samples. 
 
 12. REHEARING. Samples which represent rejected hydrated lime shall 
 be preserved in air-tight containers for five days from the date of 
 the test report. In case of dissatisfaction with the results of the 
 tests, the manufacturer may make claim for a rehearing within 
 that time. 
 
APPENDIX III. 
 
 QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR 
 HYDRATED LIME MORTAR 
 
 One bag of hydrate equals 100 pounds, 2^ cubic feet 
 
 TABLE No. 1 
 PARTS BY VOLUME 
 
 Proportions 
 Parts 
 
 Proportions 
 By 
 Volume 
 
 Volume of 
 Mortar from 
 One Bag 
 
 Quantities of Materials to 
 Make 1 Cubic Yard 
 of Mortar 
 
 Hydrate 
 
 Sand 
 
 Hydrate 
 Bags 
 
 Sand 
 Cu. Ft. 
 
 Cu. Ft. 
 
 Hydrate 
 Bags 
 
 Sand 
 Cu. Yds. 
 
 
 1 
 
 
 2.50 
 
 3.44 
 
 7.84 
 
 0.73 
 
 
 IX 
 
 2 
 
 
 3.75 
 5.00 
 
 4.61 
 5.79 
 
 5.85 
 4.66 
 
 0.81 
 0.86 
 
 
 2j^ 
 
 
 6.25 
 
 6.97 
 
 3.87 
 
 0.89 
 
 
 3 
 
 
 7.50 
 
 8.15 
 
 3.31 
 
 0.92 
 
 
 3% 
 
 
 8.75 
 
 9.32 
 
 2.90 
 
 0.94 
 
 
 4 
 
 
 10.00 
 
 10.50 
 
 2.57 
 
 0.95 
 
 
 43^ 
 
 
 11.25 
 
 11.67 
 
 2.31 
 
 0.96 
 
 
 5 
 
 1 
 
 12.50 
 
 12.85 
 
 2.10 
 
 0.97 
 
 NOTES Variations in the fineness of the sand and in the consistency of the mortar 
 may affect the yield of mortar by 10% in either direction. 
 
 Hydrated Lime requires about its own weight of water to be reduced to a paste. The 
 volume of this paste is about 90% of the volume of dry hydrate. 
 
 The volume of mortar refers to its volume in a plastic condition as mixed, not to its 
 volume after ramming or hardening. 
 
 TABLE No. 1-A 
 PARTS BY WEIGHT 
 
 Proportions 
 By 
 
 Parts 
 
 Proportions 
 By 
 Volume 
 
 Volume of 
 Mortar from 
 One Bag 
 
 Quantities of Materials to 
 Make 1 Cubic Yard 
 of Mortar 
 
 Hydrate 
 
 Sand 
 
 Hydrate 
 
 Bags 
 
 Sand 
 Cu. Ft. 
 
 Cu. Ft. 
 
 Hydrate 
 Bags 
 
 Sand 
 Cu. Yds. 
 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 
 1 
 
 IX 
 
 2 
 
 &A 
 3 
 
 &A 
 
 VA 
 
 5 
 
 
 1 
 
 IX 
 
 2 
 
 VA 
 
 3 
 
 3^ 
 4 
 4^ 
 5 
 
 2.00 
 2.46 
 2.94 
 3.44 
 3.89 
 4.37 
 4.83 
 5.31 
 5.79 
 
 13.50 
 10.96 
 9.19 
 7.84 
 6.93 
 6.17 
 5.59 
 5.08 
 4.66 
 
 0.50 
 0.61 
 0.68 
 0.73 
 0.77 
 0.80 
 0.83 
 0.85 
 0.86 
 
 87 
 
QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR. 
 HYDRATED LIME MORTAR WITH ADDITION OF PORTLAND CEMENT. 
 
 TABLE No. 2 
 PARTS BY VOLUME 
 
 Proportions 
 
 Proportions 
 
 Pounds of Portland Cement 
 
 by 
 
 For One Cubic Yard 
 
 Required for Each Per Cent. Added 
 
 Parts 
 
 by Volume 
 
 
 
 
 Hydrate 
 
 Sand 
 
 5% 
 
 10% 
 
 15% 
 
 20% 
 
 25% 
 
 Hydrate 
 
 Sand 
 
 Bags 
 
 Cu. Yds. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 
 2 
 
 4.66 
 
 0.86 
 
 23 
 
 46 
 
 70 
 
 92 
 
 115 
 
 
 2j^ 
 
 3.87 
 
 0.89 
 
 19 
 
 39 
 
 58 
 
 78 
 
 97 
 
 
 3 
 
 3.31 
 
 0.92 
 
 16 
 
 32 
 
 48 
 
 64 
 
 83 
 
 
 3/^2 
 
 2.90 
 
 0.94 
 
 15 
 
 29 
 
 43 
 
 58 
 
 72 
 
 
 4 
 
 2.57 
 
 0.95 
 
 14 
 
 27 
 
 40 
 
 51 
 
 64 
 
 1 
 
 4/^ 
 
 2.31 
 
 0.96 
 
 12 
 
 23 
 
 35 
 
 46 
 
 58 
 
 1 
 
 5 
 
 2.10 
 
 0.97 
 
 11 
 
 22 
 
 33 
 
 44 
 
 54 
 
 NOTES Variations in the fineness of the sand and in the consistency of the mortar may 
 affect the yield of mortar by 10% in either direction. 
 
 The amount of Portland cement added is a percent of the amount of Hydrate used. 
 A cubic foot of dry hydrate weighs 40 Ibs. 
 A cubic foot of Portland cement weighs 100 Ibs. 
 
 TABLE No. 2-A 
 
 PARTS BY WEIGHT 
 
 Proportions 
 
 by 
 Parts 
 
 Proportions 
 For One Cubic Yard 
 by Volume 
 
 Pounds of Portland Cement 
 Required for Each Per Cent. Added 
 
 Hydrate 
 
 Sand 
 
 Hydrate 
 Bags 
 
 Sand 
 Cu. Yds. 
 
 5% 
 Lbs. 
 
 10% 
 Lbs. 
 
 15% 
 Lbs. 
 
 20% 
 Lbs. 
 
 25% 
 Lbs. 
 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 
 2 
 
 V/2 
 3 
 
 3K 
 
 4^ 
 5 
 
 9.19 
 7.84 
 6.93 
 6.17 
 5.59 
 5.08 
 4.66 
 
 .68 
 .73 
 
 .77 
 .80 
 .83 
 .85 
 .86 
 
 46 
 39 
 35 
 31 
 
 28 
 25 
 23 
 
 92 
 78 
 69 
 62 
 56 
 51 
 47 
 
 138 
 118 
 104 
 93 
 84 
 76 
 70 
 
 184 
 157 
 139 
 123 
 111 
 102 
 93 
 
 230 
 196 
 173 
 154 
 140 
 127 
 116 
 
 88 
 
QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR. 
 
 CEMENT MORTAR WITH HYDRATED LIME ADDITIONS. 
 
 TABLE No. 3 
 
 
 
 Volume 
 
 
 
 Proportions by 
 Parts, Weight 
 
 Proportions 
 by 
 
 Re- 
 sulting 
 
 Quantities to 
 Make 1 Cubic 
 
 Pounds of Hydrate 
 Required for Each Percent 
 
 or Volume 
 
 Volume 
 
 Mortar 
 
 Yard of 
 
 Added 
 
 
 
 Cu. Ft. 
 
 Mortar 
 
 
 
 
 
 
 From 
 
 
 
 
 
 
 
 
 C ement 
 
 Sand 
 
 Cement 
 
 Sand 
 
 1 Bbl. 
 
 Cement 
 
 Sand 
 
 5% 
 
 10% 
 
 15% 
 
 20% 
 
 25% 
 
 
 
 Bbls. 
 
 Cu. Ft. 
 
 Cement 
 
 Bbls. 
 
 Cu. Yd. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 Lbs. 
 
 1 
 
 2 
 
 1 
 
 7.6 
 
 10.0 
 
 2.70 
 
 .76 
 
 50 
 
 101 
 
 151 
 
 202 
 
 252 
 
 1 
 
 2^ 
 
 1 
 
 9.5 
 
 11.8 
 
 2.29 
 
 .81 
 
 43 
 
 86 
 
 129 
 
 172 
 
 215 
 
 1 
 
 3 
 
 1 
 
 11.4 
 
 13.7 
 
 .97 
 
 .83 
 
 38 
 
 74 
 
 111 
 
 148 
 
 186 
 
 1 
 
 SH 
 
 1 
 
 13.3 
 
 15.5 
 
 1.74 
 
 .86 
 
 32 
 
 65 
 
 97 
 
 130 
 
 162 
 
 1 
 
 4 
 
 1 
 
 15.2 
 
 17.3 
 
 1.56 
 
 .88 
 
 29 
 
 58 
 
 87 
 
 116 
 
 145 
 
 1 
 
 4^ 
 
 1 
 
 17.1 
 
 19.1 
 
 1.41 
 
 .89 
 
 26 
 
 53 
 
 79 
 
 106 
 
 132 
 
 1 
 
 5 
 
 1 
 
 19.0 
 
 21.0 
 
 1.28 
 
 .90 
 
 24 
 
 48 
 
 72 
 
 96 
 
 120 
 
 NOTE Variations in the fineness of the sand and in the consistency of the mortar may 
 affect the yield of mortar by 10% in either direction. 
 
 The amount of Hydrated Lime is a percent of the amount of Portland cement used. 
 
 QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTARS 
 HYDRATED LIME-PORTLAND CEMENT MORTAR 
 
 Equal Parts of Hydrate and Cement 
 
 TABLE No. 4 
 PARTS BY VOLUME 
 
 Proportions 
 
 
 Volume of 
 
 Quantities of Materials 
 
 by 
 
 Proportions by 
 
 Mortar from 
 
 to Make 1 Cubic Yard 
 
 Parts 
 
 Volume 
 
 1-40 Ib. Bag 
 
 
 
 
 TT -J_~J-^ OM/J 1 
 
 
 
 
 
 Hydrate 
 
 Cement 
 
 
 100 Ib. Bag 
 
 Hydrate 
 
 Cement 
 
 Sand 
 
 Hy- 
 
 Ce- 
 
 
 40 Lbs. 
 
 100 Lbs. 
 
 Sand 
 
 Cement 
 
 40 Ib. 
 
 100 Ib. 
 
 Cu. Yd. 
 
 drate 
 
 ment 
 
 Sand 
 
 Bag 
 
 Bag 
 
 Cu. Ft. 
 
 Cu. Ft. 
 
 Bag 
 
 Bag 
 
 
 1 
 
 1 
 
 3 
 
 
 
 3 
 
 4.18 
 
 6.46 
 
 6.46 
 
 0.72 
 
 1 
 
 1 
 
 4 
 
 
 
 4 
 
 5.13 
 
 5.26 
 
 5.26 
 
 0.77 
 
 1 
 
 1 
 
 5 
 
 
 
 5 
 
 6.08 
 
 4.44 
 
 4.44 
 
 0.82 
 
 1 
 
 
 6 
 
 
 
 6 
 
 7.03 
 
 3.84 
 
 3.84 
 
 0.85 
 
 1 
 
 
 7 
 
 
 
 7 
 
 7.98 
 
 3.38 
 
 3.38 
 
 0.87 
 
 1 
 
 
 8 
 
 
 
 8 
 
 8.93 
 
 3.02 
 
 3.02 
 
 0.89 
 
 1 
 
 
 9 
 
 
 
 9 
 
 9.88 
 
 2.73 
 
 2.73 
 
 0.91 
 
 1 
 
 
 10 
 
 
 
 10 
 
 10.83 
 
 2.49 
 
 2.49 
 
 0.92 
 
 NOTE Variation in the fineness of the sand and in the consistency of the mortar may 
 affect the yield of mortar by 10% in either direction. 
 
 The volume of mortar refers to its volume in a plastic condition as mixed, not to its 
 volume after ramming or hardening. 
 
 89 
 
QUANTITIES OF MATERIAL FOR ONE CUBIC YARD OF RAMMED CON- 
 CRETE SHOWING ALSO THE AMOUNT OF HYDRATED LIME ADDED 
 
 TABLE No. 5 
 
 Proportions 
 
 by 
 
 Parts 
 
 Proportions 
 
 by 
 
 Volume 
 
 Quantities 
 for 
 One Cubic Yard 
 
 Pounds of Hydrated Lime 
 Added for 
 One Yard Mixture 
 
 Cement 
 
 Sand 
 
 Stone 
 
 Cement 
 Bbls. 
 
 Sand 
 Cu. ft. 
 
 Stone 
 Cu. ft. 
 
 Cement 
 Bbls. 
 
 Sand 
 Cu. yd 
 
 Stone 
 Cu. yd 
 
 5% 
 Ibs. 
 
 10% 
 
 Ibs. 
 
 15% 
 Ibs. 
 
 20% 
 Ibs. 
 
 25% 
 Ibs. 
 
 
 1 
 1 
 1 
 
 2 
 
 2H 
 3 
 
 1 
 1 
 1 
 
 3.8 
 3.8 
 3.8 
 
 7.6 
 9.5 
 11.4 
 
 2.73 
 2.45 
 2.20 
 
 0.38 
 0.34 
 0.31 
 
 0.77 
 0.86 
 0.94 
 
 51 
 46 
 41 
 
 103 
 92 
 83 
 
 154 
 138 
 124 
 
 206 
 184 
 165 
 
 257 
 230 
 206 
 
 
 VA 
 
 l l /2 
 
 iy 2 
 
 2 
 
 &A 
 3 
 
 1 
 1 
 1 
 
 5.7 
 5.7 
 5.7 
 
 7.6 
 9.5 
 11.4 
 
 2.40 
 2.18 
 2.00 
 
 0.51 
 0.46 
 0.42 
 
 0.68 
 0.77 
 0.84 
 
 45 
 41 
 37 
 
 90 
 82 
 75 
 
 135 
 123 
 113 
 
 180 
 164 
 150 
 
 225 
 205 
 188 
 
 
 2 
 2 
 2 
 2 
 
 3 
 
 3^ 
 4 
 
 4^ 
 
 1 
 1 
 1 
 1 
 
 7.6 
 7.6 
 7.6 
 7.6 
 
 11.4 
 13.3 
 15.2 
 17.1 
 
 1.81 
 1.68 
 1.57 
 1.48 
 
 0.51 
 0.47 
 0.44 
 0.42 
 
 0.76 
 0.83 
 0.88 
 0.94 
 
 34 
 31 
 
 29 
 
 28 
 
 68 
 63 
 59 
 56 
 
 102 
 94 
 88 
 
 84 
 
 136 
 125 
 117 
 112 
 
 170 
 156 
 146 
 140 
 
 
 &A 
 &A 
 &A 
 &A 
 &A 
 
 &A 
 
 VA 
 
 3 
 
 3>i 
 4 
 4^ 
 5 
 5^2 
 6 
 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 
 9.5 
 9.5 
 9.5 
 9.5 
 9.5 
 9.5 
 9.5 
 
 11.4 
 13.3 
 15.2 
 17.1 
 19.0 
 20.9 
 22.8 
 
 1.66 
 1.55 
 .46 
 .37 
 .30 
 .23 
 .17 
 
 0.58 
 0.55 
 0.51 
 0.48 
 0.46 
 0.43 
 0.41 
 
 0.70 
 0.76 
 0.82 
 0.87 
 0.92 
 0.95 
 0.99 
 
 31 
 
 29 
 
 27 
 26 
 24 
 23 
 
 22 
 
 62 
 58 
 55 
 52 
 49 
 46 
 44 
 
 93 
 
 87 
 82 
 78 
 73 
 69 
 66 
 
 124 
 116 
 110 
 104 
 96 
 92 
 88 
 
 155 
 145 
 137 
 130 
 123 
 115 
 110 
 
 127 
 120 
 115 
 110 
 105 
 100 
 95 
 90 
 87 
 
 1 
 1 
 1 
 
 1 
 1 
 1 
 1 
 1 
 1 
 
 3 
 3 
 3 
 3 
 3 
 3 
 3 
 3 
 3 
 
 4 
 
 4^ 
 5 
 5^ 
 6 
 6^ 
 7 
 7^ 
 8 
 
 
 11.4 
 11.4 
 11.4 
 11.4 
 11.4 
 11.4 
 11.4 
 11.4 
 11.4 
 
 15.2 
 17.1 
 19.0 
 20.9 
 
 22.8 
 24.7 
 26.6 
 28.5 
 30.4 
 
 .36 
 .28 
 .22 
 .16 
 .11 
 .06 
 .01 
 0.97 
 0.93 
 
 0.57 
 0.54 
 0.52 
 0.49 
 0.47 
 0.45 
 0.43 
 0.41 
 0.39 
 
 0.77 
 0.81 
 0.86 
 0.90 
 0.94 
 0.97 
 0.99 
 1.02 
 1.05 
 
 25 
 
 24 
 23 
 22 
 21 
 20 
 19 
 18 
 17 
 
 51 
 
 48 
 46 
 44 
 42 
 40 
 38 
 36 
 35 
 
 76 
 
 72 
 69 
 66 
 63 
 60 
 57 
 54 
 52 
 
 102 
 96 
 92 
 
 88 
 84 
 80 
 76 
 72 
 70 
 
 1 
 
 1 
 1 
 1 
 1 
 1 
 
 4 
 4 
 4 
 4 
 4 
 4 
 
 5 
 
 6 
 7 
 8 
 9 
 10 
 
 
 15.2 
 15.2 
 15.2 
 15.2 
 15.2 
 15.2 
 
 19.0 
 22.8 
 26.6 
 30.4 
 34.2 
 38.0 
 
 1.08 
 0.99 
 0.92 
 0.85 
 0.80 
 0.75 
 
 0.61 
 0.56 
 0.52 
 0.48 
 0.45 
 0.42 
 
 0.76 
 0.84 
 0.91 
 0.96 
 1.01 
 1.06 
 
 20 
 18 
 17 
 16 
 15 
 14 
 
 40 
 37 
 34 
 32 
 30 
 28 
 
 60 
 55 
 51 
 
 48 
 45 
 
 42 
 
 80 
 74 
 68 
 64 
 60 
 56 
 
 100 
 92 
 85 
 80 
 
 75 
 70 
 
 1 
 
 5 
 
 10 
 
 1 
 
 19.0 
 
 38.0 
 
 0.69 
 
 0.49 
 
 0.97 
 
 13 
 
 26 
 
 39 
 
 52 
 
 65 
 
 NOTES The above table for quantities of cement has been taken from Taylor & Thomp- 
 son's "Concrete, Plain and Reinforced." The quantities of hydrated lime have been cal- 
 culated by the author. 
 
 In many instances the amounts are even fractions of a sack of hydrate (100 Ibs.), i. e., 
 10% in a 1-2-4 is practically half a sack. 
 
 In case where the amount of hydrate called for is not a convenient part of a sack, it is 
 advisable to have a box made which will hold the required amount. This is easily done, as 
 a cubic foot of hydrate weighs 40 Ibs. A one sack mixture would require the addition of % 
 the amount of materials and a 2 sack mixture of ^ the amount. 
 
 90 
 
INDEX 
 
 SUBJECT Page 
 
 Aluminum 1213 
 
 Arenaceous Limestone 21 
 
 Argillaceous Limestone 21 
 
 Atom 11 
 
 Atomic Weights 12 
 
 B 
 
 Barrel 81 
 
 Basic Carbonate , 38 
 
 Brigham, S. Y 42 
 
 Brewer, Bertram 74 
 
 Bucket Size 83 
 
 Burning, Chemical change 14 
 
 Bushel 81 
 
 C 
 
 Calcium 12-13 
 
 Carbon 12-13 
 
 Carbonates 13 
 
 Cement Hydrated Lime Mortar Quantities 89 
 
 Chalk 21 
 
 Chapman, Cloyd M 35 to 37 
 
 Chemistry of Lime 11 to 20 
 
 Chemical Symbols 12 
 
 Classification 21 
 
 Coal 31 
 
 Composition Calculation 18-19 
 
 Compound 11 
 
 Concrete Cracking 66 
 
 Concrete Quantities of Materials 90 
 
 Concrete Water Proofing 70 to 77 
 
 Conglomerate Limestone 21 
 
 D 
 
 Dolomite Limestone 21 
 
 91 
 
SUBJECT p age 
 E 
 
 Edfou 10 
 
 Egypt 9 
 
 Eldred Process 31 
 
 Element 1 1 
 
 Emley, Warren E 37-56 
 
 Etruscans ; ; . . 10 
 
 F 
 
 Fue 1 .....;...... 30 
 
 G 
 
 Greeks 10 
 
 H 
 
 Hardening Chemical Change 16 
 
 High Calcium Limestone 21 
 
 Historical 9-10 
 
 Hydrate Calculating Composition 19 
 
 Hydrated Lime 22 
 
 Hydrated Lime Advantage of 49 to 53-79-80 
 
 Hydrated Lime Cement Mortar Quantities 87 
 
 Hydrated Lime Chemical Composition 46 
 
 Hydrated Lime Definition 41-81 
 
 Hydrated Lime Manufacture of 41 to 45 
 
 Hydrated Lime Mortar Quantities . 87 
 
 Hydrate Paste . 82 
 
 Hydrated Lime Properties of 46 to 48 
 
 Hydrated Lime Physical Properties 47-48 
 
 Hydrated Lime Specific Gravity 47 
 
 Hydrated Lime Specification 84 
 
 Hydrated Lime Use in Concrete 63 to 77 
 
 Hydrated Lime Use of 49-50 
 
 Hydrated Lime Weight 47-81 
 
 Hydrates 13 
 
 Hydrating Chemical Change 15 
 
 Hydrating Dodge Process 42 
 
 Hydrating Modern Methods of 42 
 
 Hydrating Clyde Process 42-43 
 
 Hydrating Kritzer Process 43-44 
 
 Hydrating Pierce Process 42 
 
 Hydrating Reaney Process 43 
 
 Hydrating Lauman Process 45 
 
 Hydraulic Lime 22 
 
 Hydrogen 12-13 
 
 Hydroxides 13 
 
 92 
 
SUBJECT Page 
 
 I 
 
 Iron 12-13 
 
 J 
 
 Jackson, Chas. T 25 to 27 
 
 K 
 
 Kiln Aalborg 30 
 
 Kiln Continuous 24-26 
 
 Kiln Draw 26-27 
 
 Kiln Field 25-26 
 
 Kiln Intermittent 24 
 
 Kiln Pot 24-25-26 
 
 Kiln Producer Gas . 31 to 32 
 
 Kiln Ring 26 
 
 Kiln Rotary 26-30 
 
 Kiln Schofer 30 
 
 Kiln Steel Encased 28 to 30 
 
 Kilns Types 24 
 
 Kiln Vertical 26-28 to 30 
 
 L 
 
 Lazell, E. W 56-72-73 
 
 Lime Calcium 22 
 
 Lime Chemistry 11 to 20 
 
 Lime Classification of 21 to 23 
 
 Limestone Classes of 21 
 
 "Lime Cycle" 16-17 
 
 Lime Definition 22-84 
 
 Lime Fat 23 
 
 Lime Ground 22 
 
 Lime High Calcium 22 
 
 Lime High Magnesium 22 
 
 Lime Hydrated 22 
 
 Lime Hydraulic 23 
 
 Lime Hydraulic Definition 22 
 
 Lime Lean 23 
 
 Lime Magnesium 22 
 
 Lime Manufacture of 24 to 33 
 
 Lime Overburned 38 
 
 Lime Paste 81 
 
 Lime Paste Aging 38 
 
 Lime Paste Volume 81 
 
 Lime Paste Water in 36-37 
 
 93 
 
SUBJECT p age 
 
 Lime Pulverized 22 
 
 Lime Run of Kiln 22 
 
 Lime Selected Lump 22 
 
 Lime Slaking 34 to 40 
 
 Lime Types 22 
 
 Lime Weight 81 
 
 Limestone Composition 21 
 
 Limestone -Definition 21 
 
 Limestone Origin 21 
 
 M 
 
 Magnesium 12-13 
 
 Magnesium Limestone 21 
 
 Marble 21 
 
 Marl 21 
 
 Mass 11 
 
 Miller 9 
 
 Molecular Weight 12 
 
 Molecule 11 
 
 Mortars 49 to 62 
 
 Mortar Brick or Tile 54-55 
 
 Mortar Cement Lime 56 to 62 
 
 Mortar Definition 83 
 
 Mortar Hydrated Lime Quantities 87 
 
 Mortar Metal Lath 54 
 
 Mortar Mixing Machine 52 
 
 Mortars Specifications 53-54-55 
 
 Mortar Strength of 56 to 60 
 
 Mortar Tests of 57 to 60-72 to 75 
 
 Mortar Wood Lath 53-54 
 
 Mortar Weight 83 
 
 
 
 Ombos 10 
 
 Oolite 21 
 
 Oxides 13 
 
 Oxygen 12-13 
 
 Oxy-hydrate 38 
 
 P 
 
 Palladius 10 
 
 Permeability Tests 72 to 75 
 
 Plasterers Co 10 
 
 Plastic Definition 63 
 
 Plasticity Concrete 63-66 
 
 Pliny 10 
 
 Portland Cement Barrel 82 
 
 94 
 
SUBJECT Page 
 
 Portland Cement Definition 82 
 
 Portland Cement Paste 82 
 
 Portland Cement Weight 82 
 
 Producer Gas 31 
 
 Pyramids 9 
 
 Pyramids Cheops 10 
 
 R 
 
 Romans ^ .................. 10 
 
 8 
 
 Sack Hydrate , 82 
 
 Sand Quality 
 
 Sand Specific Gravity 82 
 
 Sand Specifications for 52 
 
 Sand Weight 82 
 
 Sand Voids 82 
 
 Shovels Size 83 
 
 Silicon 12-13 
 
 Slaking "Burned" in 34-37-81 
 
 Slaking Chemical Change 15-34-81 
 
 Slaking Chemical Changes 34 
 
 Slaking Drowned 35-81 
 
 Slaking Dry Methods 41 
 
 Slaking Italian Method 39 
 
 Slaking Methods of 34 
 
 Slaking Roman Method 38 
 
 Slaking Water Required 35-36-37-81 
 
 Specification Cement Hydrate Mortar 62 
 
 Stucco 10 
 
 Sulphur 12-13 
 
 T 
 
 Thomaston, Me 25-26 
 
 Thompson, Sanford E 74-75 
 
 r 
 
 Vicat 9 
 
 Vitruvius 10-38 
 
 W 
 
 Wheelbarrows Size 83 
 
 Woolson, Ira H 56 
 
 Wright, W. H 23 
 
 95 
 
off 
 
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